. V9 . -«s REESE LIBRARY UNIVERSITY OF CALIFORNIA. - vf.1- • r; '«fr«fiFia?*,&r*r <« 5siF LTVM* v%«M%'^^vMW' -^£4, tf iw3B,?-46j vS f^fT^^^^T^ ^^^C^^^^#4^ ^ -37%<^^^Tt^.T^^^;»w ?#SSS®ip ^^^^is^ljffir^i^K ^^§^?^^l|^&i^?^% * fc% r/& f%l ffi?» ^i&" -vX^> RtLt-^ViT^fi TREATISE MINERALOGY. EDINBURGH: PRINTED AT THE CALEDONIAN MERCURY PRESS. TREATISE MINERALOGY, NATURAL HISTORY OF THE MINERAL KINGDOM. FREDERICK J^OHS, PROFESSOR IN THE MINING ACADEMY OF FREIBERG. Translated from the German, with considerable Additions, HY "WILLIAM HAIDINGER, F.R.S.E. OF THE UNIVERSITY J VOL. II. EDINBURGH : PRINTED FOR ARCHIBALD CONSTABLE AND CO. EDINBURGH j AND HURST, ROBINSON, AND CO. LONDON. 1825. CONTENTS OF VOL. II. PART V. PHYSIOGEAPHY. §. 253. Definition . . y . 1 §. 254. Objects of Physiography . V * 2 §. 255. General Description of the Species . * 3 §. 256. Arrangement of the General Description T* £ §. 257. The Collective Descriptions do not depend upon the Systems . • . 14 GENERAL DESCRIPTIONS OF THE SPECIES. CLASS I. ORDER I. Gas ... 17 OBDER II. Water , * .21 ORDER III. Acid . » . 22 ORDER IV. Salt . . 27 CLASS II. ORDER I. Haloide *. . 57 ORDER II. Baryte . „ .101 ORDER III. Kerate . . 154 ORDER IV. Malachite . . .158 ORDER V. Mica . . . 178 ORDER VI. Spar . . .206 ORDER VII. Gem ... 293 ORDER VIII. Ore . . 373 ORDER IX. Metal . 423 ORDER X. Pyrites . . .446 96985 PART V. PHYSIOGRAPHY. §. 253. DEFINITION. Physiography means the description of natu- ral productions (§. 17.). It is intended to pro- duce a distinct image of those objects which we dis- tinguish from each other by means of the Charac- teristic, and denominate conformably to the rules laid down in the Nomenclature. Physiography is not adapted to the purpose of distin- guishing minerals. We cannot by its assistance find the place of a given mineral in the system ; or, in other words, recognise it : for it is independent of that con. nexion among natural productions upon which systems are founded, and considers them singly, every one by itself. Physiography, therefore, cannot acquiesce in considering single characters or characteristic marks ; but it must ex- hibit them all, if the image it produces is meant to be a complete and satisfactory one. Its difference from the Characteristic, founded upon these properties, is as obvious as the impossibility of substituting the one instead of the other. A description, therefore, is not a character (§. 242.) ; since the peculiarity of every character consists in its being composed of a smaller number of characteristic terms than may be observed in the objects characterized. The descriptions presuppose nothing but Terminology. It is perfectly indifferent what nomenclature is made use of in Physiography, provided only the names and denomi- nations to which the descriptions of the species refer, an- swer the purpose of keeping separate those objects, which VOL; ii. A 2 PHYSIOGRAPHY. §. really differ from each other. If that department of Na- tural History to which the Physiography belongs, possesses the advantage of a systematic nomenclature, this will be preferable in its application to any other, since it is the only one which deserves to be called scientific. The Determinative and the Descriptive parts of Minera- logy have never been distinctly kept separate from each other, and this has been the reason why neither of them has yet attained that degree of perfection and utility of which it is susceptible, even in the present state of Mineralogy, and with our limited knowledge of the productions of the Mineral Kingdom. Every thing was expected from the Descriptive part of Natural History, while the Determina- tive part was entirely lost sight of; and thus Mineralogy has remained far behind her sister sciences, Zoology and Botany. §. 254. OBJECTS OF PHYSIOGRAPHY. The object to which Physiography refers, in the Natural History of the Mineral Kingdom, in as far as it produces a mere description, is the Individual. Any description, containing the indication of all the pro- perties, will suffice for determining a particular individual. In the Animal and Vegetable Kingdoms, homogeneous in- dividuals (§. 220.) are in most cases at the same time iden- tical (§. 214.), excepting their sexual differences ; or at least the deviations occurring in their single characters may be considered as merely accidental. One indi- vidual therefore, or in the case of an existing difference in the sexes, two of them, will represent the whole species ; and the description of these individuals may be received in the place of a description of the whole species. In the Mineral Kingdom, the homogeneous individuals in most cases so widely differ from each other, that a descrip- tion of the one does not by any means apply to another ; one, or a few of them, therefore, cannot represent the §. 255:* PHYSIOGRAPHY* 3 whole species, nor can their description be substituted in- stead of the description of the species. The description of all the varieties of a species does not produce a clear idea or representation of the species itself; because the species is not a single body, but the assemblage of all the homoge- neous individuals or varieties (§. 220.). Thence we infer that the species in Mineralogy is not properly an object for a description ; and the latter will not therefore allow of the same use in the Mineral Kingdom, to which it is adapted in the Animal and Vegetable Kingdoms. In the Mineral Kingdom, only individuals (or composi- tions (§. 23.) of individuals), admit of being described, and this is effected by indicating all their natural-historical pro- perties. In enumerating these, it is useful to keep to a cer- tain determined, though in itself arbitrary order of succes- sion, which, for the sake of perspicuity, should remain unal- tered, if it has once been fixed upon. All prolixity should be carefully avoided, every superfluous word, every not per- fectly determined expression, in short, every thing foreign to the purpose, should be rejected ; and such terms em- ployed as are explained in the Terminology. Many obser- vations apply also to the present subject, which have been made to the same purpose in the introduction to the Cha- racteristic. Descriptions are required, whenever there occur new varieties of a species, the latter being either already known, or entirely new ; they are also useful in such varieties as are distinguished by a particular application, or any remarkable property, or such as have been provided with particular names in the arts of life. In the latter, it is only necessary to indicate those properties, by which the variety in ques- tion differs from other varieties of the same species. It is very useful to give an accurate description of such indivi- duals, as are subjected to a chemical analysis. §. 255. GENERAL DESCRIPTION OF THE SPECIES. In order to represent the natural-historical spc- 4 PHYSIOGRAPHY. §. £55. ties in the Mineral Kingdom, it is necessary to construct a Collective or General Description. The problem to be resolved in constructing a General Description is, to give a correct idea of all, or at least of the known varieties of a species in their proper connexion ; it must therefore contain at once all the descriptions of these varieties, without its being itself in a strict sense a description at all. It is evident that the only means of ar- riving at this end, will be the employment of the series of characters. The method of constructing a general description of a species is as follows. First, any suitable variety of the species is chosen, and described with all possible accuracy, the single characters succeeding each other agreeably to the order fixed upon, as above mentioned. The descrip- tion will contain only single characters, consisting of a certain form, a certain colour, a certain kind of lustre, a certain degree of hardness or of specific gravity, &c., all of these being members of their respective series. If in the place of every one of these single characters, we substitute the complete series to which it belongs, the Description cs the Individual^ or of the variety, is transformed into the Collective or General Description of the Species. The characters contained in the general description are expressed in series, produced either by immediate observa- tion and interpolation, or by derivation (§. 79-)' The cha- racters in the descriptions of determined varieties consist of single members of these series. Evidently the collective description not only produces a complete idea of the species itself, but it also contains the individual description of every one of its single varieties ; for, as to the latter, if we choose arbitrarily any single member from every one of the men- tioned series, and join these members in the adopted order of succession, the result will be the description of a variety, belonging to the species. The representation of the species as contained in the ge- neral description, is far more complete, than it could be ob- tained by immediate observation ; for it unites all the va- §. 255. PHYSIOGRAPHY. 5 rieties which may be produced by all possible combinations of the single properties (the members of different series). It would contain all the varieties possible in a species, if the series themselves were complete, which can be maintained only of those produced by derivation. Thus the conside- rations referring to the Mineral Kingdom become both fer- tile and interesting ; because, by means of the general de- scription, we obtain from every newly discovered variety, though it should differ from those already known, only in a single character, an almost endless number of new varieties, which may be produced by uniting the new- ly discovered property with every combination of the members of the other series, which the general descrip- tion contains. The same process of reasoning is fol- lowed here, by which we obtain from a newly ascertained co-efficient, or from a number of derivation not known be- fore, not merely a single form, but whole series of such forms. The pure, or properly so called, general description, re- fers only to the individuals of the species, because it is only from these that we are entitled to derive characteristic marks, fit for being employed in Natural History (§. 192.). If the compound varieties are to be noticed, this must be done without mixing them up with the simple ones. From the preceding observations, it appears that the ge- neral description pre-supposes the correct idea of the natu- ral-historical species ; but none besides of the general ideas developed in the Theory of the System (§. 17-). The collective description explained here has no doubt been the fundamental idea of the descriptions introduced in Oryctognosy by the celebrated WERNER. In these too series are made use of; and supposing the determination of the species to be correct, they might be employed in the place of the general descriptions of this work, if those se- ries, upon which their completeness and utility more particu- larly depends, had been known at an earlier period, and the compound varieties properly separated from the simple ones. The general description requires in particular, that the 6 PHYSIOGRAPHY. §. 256. rules be strictly followed which have been mentioned in §. 244., in respect to the Characteristic. §. 250. ARRANGEMENT OF THE GENERAL DESCRIP- TION. The general or collective descriptions require to be so arranged, as to facilitate their use as much as possible, and to produce, in fact, a complete gene- ral view of the species. An example taken from one of the general descriptions contained in this Treatise, will be the best means to shew their arrangement in a greater detail ; for which purpose, we select that of rhombohedral Lime-haloide, which is par- ticularly well calculated for illustration, on account of the numerous varieties which this species comprehends. In order to determine the series of crystallisation of a species in general, it is necessary to indicate its funda- mental form with its dimensions expressed by numbers. The authority has been given in the forms of variable di- mensions. Those which have been re-examined, or newly or more accurately determined, are likewise indicated by the addition of R. G. (Reflective Goniometer) or AP. (approxi- mation) ; the first expressing a higher degree of exactitude. The angles or dimensions of every one of these which can possibly occur in the species, may be calculated from the fundamental form, agreeably to the rules laid down for the derivations of other simple forms. For the sake of greater convenience in calculating the angles of rhombo- hedral Lime-haloide, the value of a, the axis of the funda- mental form, has been given ; its horizontal projection being supposed =5= 1. The same is observed in forms of the Py- ramidal system. In the fundamental forms belonging to the Prismatic system, the ratio of the axis and the two dia- gonals, a : b : c has been given ; in Hemi-prismatic forms the ratio of the four lines a : b : c : d, as explained in §.98. §. 256. PHYSIOGRAPHY. 7 Yet a calculation would always be required, if we intended to find the angles of the simple forms from the given value of the axis, or from that of the mentioned ratios between the axis and the diagonals ; and as it is useful and interesting to know what simple forms have already been observed, or wliich among these most commonly occur in the species ; the derived forms have also been indicated, along with the measure of their angles, and expressed by means of their crystallographic signs. In respect to the indication of their angles, a general exception has been made in those limit- ing forms, in which a similar determination is not neces- sary, since their angles are the same wherever they occur, and have been given in their proper place, under the head of Terminology. An asterisk over the crystallographic sign of a simple form denotes, that it has been observed in nature, without any additional faces. The peculiar mode in which the simple forms of a spe- cies join in combinations, is another very important subject in the general outline of that species; it is the Character of Combinations (§. 145., &<%). The simple forms of octahe- dral Fluor- haloide, those of hexahedral Iron-pyrites and of tetrahedral Copper-glance, belong to one and the same series of crystallisation, and yet every one of these species contains some simple forms not to be met with in the others, and which nevertheless impart a peculiar aspect to the com- binations in which they enter, so that the crystallisations of the three species differ most essentially from each other. This difference is expressed in the Character of Combina- tions, which is tessular (§. 15C.) in the Fluor-haloide, semi, tessular of parallel faces (§. 157-) in the Iron-pyrites, and semi- Icssiilar of inclined faces (§. 15?.) in the Copper-glance. In the rhombohedral system, the combinations are either rhombo- hedral or di-rhombohedral, or hemi-rhombohedral, &c. agreeably to §. 145., &c. The first of these applies to the species of rhombohedral Liuie-haloide, and its Character of Combinations therefore is rhombohedral. Next to this are indicated some of the most common or remarkable combinations occurring in the species, expressed 8 PHYSIOGRAPHY. §. 256. by their crystallographic signs, and partly also illustrated by figures. It may be supposed here, that the use of the signs will be entirely familiar to those who have read the preceding part of the present work. Upon this supposition the few lines referring to the combinations will be more useful to the reader, than the descriptions of crystalline forms commonly to be met with in mineralogical books, which, though sometimes extended to several pages, yet seldom suffice for representing with any degree of accuracy, combinations of three or four simple forms, far less such as are still more complicated. These descriptions never can arrive at any thing like mathematical precision, whereas the crystallographic designation employed in this work ad- mits of the most accurate calculations, and will answer every crystallographic question, which regards the desig- nated compound form. The phenomenon of cleavage being in the nearest rela- tion to the crystalline forms, the next place in the col- lective description has been assigned to it. The forms of cleavage are likewise represented by means of their crystal- lographic signs ; and as to the faces of cleavage, due atten- tion has been paid to their degree of perfection, some of them being more easily observed, and on that account dis- tinguished from others, which require a more minute ex- amination, sometimes even the assistance of a very intense light (§. 162.). Thus in rhombohedral Lime-haloide the faces of cleavage obtained in the direction of the faces of the rhombohedron R, commonly present high degrees of perfection, while thos2 in other directions, if ever they occur, generally appear less distinctly. Fracture, as far as it is contained in the collective de- scription itself, refers only to simple minerals. Although in itself rather insignificant, yet for the sake of complete- ness we cannot pass it by unnoticed. Several varieties of fracture, if mentioned in one and the same place, denote the limits, between which the varieties range, which occur in the species. Also in respect to fracture, it will be indi- cated, whether it be easily or difficultly obtained, lihom- §. 256. PHYSIOGRAPHY. 9 bohedral Lime-haloide so very readily yields to cleavage, that in most cases it is attended with considerable difficulty to perceive the faces of fracture, which are conchoidal. The physical quali ty of the surface of crystals is far more important than fracture, since it is in close connexion with the crystalline forms themselves. Also these faces are ex- pressed by crystallographic signs, because they cannot be indicated with greater brevity or precision. Several of the faces of crystallisation of rhombohedral Lime-haloide are very often found to be streaked ; but these striae, with a few trifling exceptions, have a constant direction, being almost in every instance parallel to the intersection of the striated faces with the faces of the rhoinbohedron R. The characters depending upon the presence of light, contribute very much to enliven the image or representa- tion of the species. The kinds of lustre must everywhere be mentioned ; and if there should be found a difference as to its occurrence upon different faces, also the direction must be given, in which the different kinds of lustre may be observed. In rhombohedral Lime-haloide, the lustre is in general vitreous, only the faces of R — CD sometimes pre- sent pearly lustre. The latter kind of lustre sometimes also extends to compound varieties, whose faces of compo- sition correspond to those of II — cs, as in the well known example of Slate-spar. Of the degrees of lustre, it is suffi- cient to mention the limits. The series of colours in particular might be very useful in enlivening the collective descriptions, if they could be expressed with the same conciseness as those of the crys- talline forms. But in order to indicate the series, it is in- dispensable to mention all its single members ; and I have therefore thought more convenient, for the sake both of precision and brevity, merely to give an outline of these series, by indicating their principal points, or some of their more peculiar properties. This mode of treating the sub- ject does by no means injure the use of the series of co- lours, nor diminish their importance in the determination of the species. It is the white colour, which, in rhombohe- 10 PHYSIOGRAPHY. §. 256. dral JLime-haloide, accidentally inclines to several others, none of their different shades possessing any degree of brightness. Co1 ours produced by occasional admixtures or' minerals foreign to the species, do not properly belong to the collective description ; because they are not mem- bers of the series of colours of the species described. Yet they are indicated by themselves, at least the common shades, in order to exclude them from those, with which they are not connected by transitions within the same series. It is important to indicate correctly the colour of the powder, or the streak. The indication of the limits will suffice for the degrees of transparency. In general, refraction is simple in all those species whose forms belong to the tessular system : it is double in all those of the other systems. There is but one optical axis in the rhombohedral and pyramidal systems, which coincides with the crystallographic principal axis. In the prismatic forms, there exist two optical axes, situ- ated in planes which pass through the axis and one of the diagonals. The direction of these axes, in respect to the crystallographic axes and diagonals, in most cases has not been sufficiently ascertained. The characters of the mine- rals derived from their action upon light, will no doubt form an essential part in future of the general descriptions. Lastly, the general descriptions contain the indication of the form of aggregation, of hardness, specific gravity, and other characteristic marks derived from, or respecting, the substance of minerals, as odour, taste, &c., which may be useful in the description of varieties ; all of them express- »ed with the brevity essential to the characters which com- pose the Characteristic. It is necessary to observe here, that the unity of comparison for the specific gravity of ex- pansible fluids, is that of atmospheric air ; in the same way in which that for liquid or solid bodies is the specific gravity of distilled water. The specific gravities given without adding any authority, have been newly deter- mined and reduced to a temperature of 15° centigr. (59° Fahrenh.). §. 256. PHYSIOGRAPHY. 11 A great number of the different varieties of certain spe- cies is produced by the composition of their individuals. The species of rhombohedral Lime-haloide is one of the most remarkable in this respect ; and this has been the reason of its having been divided and subdivided into a great number of sub-species and kinds. If the collective description of the simple varieties has been drawn up with sufficient accuracy, it will not be difficult to join the com- pound varieties within a narrow compass which can be easily surveyed, and annexed to the former. This has been done in rhombohedral Lime-haloide. Among the compound va- rieties, the most remarkable are those in which the compo- sition follows a certain rule, that is the twin-crystals. The general consideration of the twin-crystals (§. 179-) contains the principles of a method, according to which those be- longing to any particular species may be indicated with precision and convenience, and provided with an appro- priate designation. This method consists in expressing the form of the regularly joined individuals by means of their crystallographic signs, and in determining in the same way the axis of revolution and the face of composition. It will be still more general if we conceive, that not any particular observed crystalline variety, but indeed every simple or compound form belonging to the species, may be- long to the individuals, which are joined in the regular composition. It will be sufficient only to mention the imitative forms, in order to recal their properties to the memory, these be- ing commonly so much alike in every instance, that they allow of a general explanation, which has been given in its proper place (§. 181, &c.). The condition of their surface, or of the faces of composition in their interior, the shape of the particles of composition, and the mode of that compo- sition itself, may likewise be indicated. It is necessary to remark here that the occurrences of composition are not mentioned for the purpose of recognising or distin- guishing the compound varieties of rhombohedral Lime- haloide from those of any other species, which in fact £ PHYSIOGRAPHY. §. would in every respect be foreign to the purposes of a collective description ; but that they are intended mere- ly for producing a general survey of every thing relative to those compositions contained within the limits of the species. The same applies also to amorphous compositions, or, as they are more commonly called, to the massive varieties. As to these, the most important properties to be mentioned here will be, the shape of the component particles, their size, mode of aggregation and fracture ; for, according to these properties, the species of rhombohedral Lime-haloide has been divided into foliated, fibrous, and compact Lime- stone, together with their farther subdivisions ; and like- wise the oryctognostic species of Slate-spar, Anthracolite Chalk, Rock milk, and others, have been formed under the same influence of composition, as will appear more evident- ly in the Observations annexed to the description of the pre- sent species. Thus we are capable of expressing in a few words, much that has been described with great prolixity in mineralogical works ; while we enjoy the advantage of arriving at an idea of the subject, correct and general, and conformable to nature. Also the pseudomorphoses need nothing more than to be mentioned. Even though their appearance be regular, they so little refer to the internal quality of the species, that their knowledge does not add to our general know- ledge of the species. The arrangement of all the other collective descriptions is the same as that explained in the preceding example, taken from rhombohedral Lime-haloide. If other pro- perties should happen to occur than those mentioned here, these properties will likewise be inserted in a proper or. der, provided they contribute to our natural-historical knowledge of the species in question ; whereas others men- tioned in rhombohedral Lime-haloide, if they be wanting, will be passed over in silence. In general, some one or other of the natural-historical properties of the species may be rendered more prominent, the more it contributes to a §. 256. PHYSIOGRAPHY. 13 clear and distinct image of the species ; without, however, too much encroaching upon the uniformity of the collective descriptions, as far as this may be consistent with the qua- lities of the species described. The collective descriptions of the species form one of the most important subjects of the Natural History of the Mi- neral Kingdom. Although they represent the mineral species by themselves, not paying any attention to their resemblance to others, yet they effect this in the mi- nutest detail, and to the greatest possible completeness, and hence they contain all the natural-historical information, pro- perly so called, relative to the mineral productions. Cha- racter naturalls (§. 242. 243.) generum plantarum fundamen- turn est, quo de»tltutus nuttus de genere rite judicabit ; adeoque dbsolutum fundamentum cognitionis plantarum at et erit* L.TN N. Phil. Bot. 1 89. This knowledge, however, is still very imperfect. For mineralogists have hitherto attached too much importance to composition and other subordinate sub- jects, whilst the study of what alone is capable of bringing the collective descriptions of mineral species nearer perfec- tion, has comparatively been too much neglected. Hence the accurate investigation of the natural-historical proper- ties of individuals, upon which this chiefly depends, cannot be too strongly recommended for the promotion of minera- logical science. I trust that in these inquiries the perusal of the present work will remove a great part of those dif- ficulties, which have formerly originated from a too general want of crystallographic knowledge. Crystallographic in- formation being now rendered more accessible, and its ap- plication shewn by a great number of examples; in short, the path being open which ought to be followed, we may justly expect, that, within a short period, the zeal and perseverance at present bestowed upon the study of Mine- ralogy, will greatly improve the collective descriptions of the mineral species. 14 PHYSIOGRAPHY. §. 257. §. 257- THE COLLECTIVE DESCRIPTIONS DO NOT DEPEND UPON THE SYSTEMS. The collective descriptions are independent of the systems ; they are applicable, therefore, in every system, even though the principles to which it is framed should not agree with those of Natu- ral History. The collective description represents the natural-historical species developed in its minutest details. The natural-histo- rical species itself is the basis of every method, or in fact of every science, which refers to the productions of the Mineral Kingdom : it is the object, not the product of classification (§. 220. 223.). The collective description is therefore inde- pendent of the system, and may be applied in every one of them, natural or artificial, and drawn up conformably to the principles of Natural History, or to those of any other science. Thus the collective description, by means of its general applicability, is raised to a still higher de- gree of importance, since it becomes the link between Na- tural History and other sciences referring likewise to the productions of the Mineral Kingdom. Having completed the collective descriptions, Natural History has fulfilled its duty, and the natural-historical species is now fit to be the subject of farther investigation in other sciences, in all of which it is the general classifiable unity, since it is not only distinguishable with the greatest facility from every one resembling it, but also clearly re- presented to the minutest details by the enumeration of its natural-historical properties. The acquirement of all other kinds of information referring to minerals is foreign to Natural History, although its foundation consists in the correct determination of that science. It is only by di- viding and keeping separate the heterogeneous principles, that it will be possible to produce unity and connexion with- in the store of our knowledge, for by this means we shall §. 257. PHYSIOCRAPHV. 15 not only avoid future disputes and contradictions, but also terminate those which have hitherto prevailed. Every thing being thus preserved in its proper place, one will re- gularly follow the other ; and there will not exist that mix- ture of heterogeneous matter of information, which has been till now called Mineralogy, without, however, having a just title, according to its nature and principles, to be regarded as such. Every one therefore of those sciences, which have hitherto been but too frequently mixed up with one another, thus confined within their respective limits, will entirely become what it ought to be, and will not be prevented in future by foreign considerations, from approaching nearer perfection. It is of the greatest importance never to lose sight of the succession of such sciences as refer to one and the same object. Every step taken upon the methodical path, leads us forwards ; and every one is equally important, since it be- comes possible only upon the supposition of the preceding one having been accomplished. It is Natural History which takes the lead in this process ; and every scientific exami- nation of a production of nature, must therefore begin with its natural-historical determination. The following list contains some mineralogical works use- ful in a more detailed study of mineral species, and which have partly also been made use of in the physiographieal department of the present Treatise : A System of Mineralogy, in which minerals are arranged according to the Natural History method. By Robert Jameson. Third edition. Edinburgh, 1820. Manual of Mineralogy : containing an account of simple Minerals ; and also a description and arrangement of mountain rocks. By Robert Jameson. Edinburgh, 1821. An Elementary Introduction to the Knowledge of Mine, ralogy, &c. By William Phillips. Third edition. Lon- don, 1823. Handbuch der Mineralogie, von C. A. S. Hoffmann. Frei- berg, 1811. Continued by A. Breithaupt. 16 PHYSIOGRAPHY. §. 257* Handbuch der Mineralogie, von J. F. L. Hausmann. Got- tingen, 1813. Vollstandiges Handbuch der Oryktognosie, von H. Stef- fens. Halle, 1811. Handbuch der Oryktognosie, von Karl Caesar v. Leonhard. Heidelberg, 1821. Cristallographie, &c. par M. de Rome' de 1'Isle. V. Vol. I. p. 17- Traite de Mine'ralogie, par le C-". Haiiy. V. Vol. I. p. 17- Tableau comparatif des resultats de la Cristallographie et de Panalyse chimique, relativement a la classification des mine'raux, par M. 1'Abbe Haiiy. Paris, 1809. Traite' de Mine'ralogie, par M. 1'Abbe Haliy. Seconde e'dition. Paris, 1822. Numerous Memoirs in different Journals, by Messrs Haiiy, Monteiro, Count Bournon, Soret, Weiss, Bern- hardi, Fuchs, Dr Brewster, Phillips, Brooke, Le'vy, and others. For Synonymes and Literature in general, T. Allan's Mineralogical Nomenclature, alphabetically ar- ranged, &c. Edinburgh, 1819. Systematische Uebersicht der Litteratur f iir Mineralogie, Berg-und Hutten-Kunde, vom Jahr 1800 bis mit 1820, von Dr Johann Carl Freiesleben, Kon. Sachs. Bergrath. Freyberg, 1822. GENERAL DESCRIPTIONS OF THE SPECIES. CLASS I. GAS. WATER. ACID. SALT. ORDER I. GAS. GENUS I. HYDROGEN-GAS. 1. PURE HYDROGEN-GAS. Pure Hydrogen Gas. JAMESON. Man. p. 1. WasserstofF- gas. HAUSMANJT. I. S. 63. Amorphous. Transparent. Expansible. Sp. Gr. = 0-0688. BERZ. * 0-0732. BIOT and ARA- co.-f- Odour peculiar. • Larbok i Kemien, af J. J. BERZELIUS. Stockholm. f Trait^ de Physique Expe'r. et Math, par M. BIOT. Paris. VOL. II. B 18 PHYSIOGRAPHY, CLASS I. OBSERVATIONS. 1. Hydrogen-gas, as it is found in nature, is generally in a state of combination. By the assistance of chemical processes, it may be obtained free from all odour. It burns with a feeble light in atmospheric air, and if mixed with it, produces a detonating gas. It imparts neither odour nor taste to water with which it has been kept in contact. 2. The pure Hydrogen-gas is developed from several kinds of rocks, limestone, beds of coal, &c. ; also from pools and stagnant water in general ; and it is met with un- der these circumstances in different countries all over the globe. It is one of the most common sources of the per- petual fires of the Pietra Mala, and other places in Italy, in the north of Asia, &c. and occurs in several mines. 2. EMPYREUMATIC HYDROGEN-GAS. Empyreumatic or carburetted Hydrogen Gas. JAM. Man. p. 1. Kohlenwasserstoffgas. HAUSM. I. S. 64. Amorphous. Transparent. Expansible. Sp. Gr. = 0*5707. BERZ. Odour erapyreumatic. OBSERVATIONS. 1. The empyreumatic Hydrogen-gas consists of Carbon 74-00. Hydrogen 26-00, according to BERZELIUS. It burns with a very faint blue flame, and imparts neither odour nor taste to water it has been in contact with. 2. It is developed from marshes and stagnant pools, and is also found in volcanic countries. It seems that the above mentioned species, which is said by BERZELIUS to burn with almost no flame at all, is different from the in- flammable gas which occurs in coal mines, particularly those of Newcastle and Liege, since the latter burns with a bright flame. This gas is called fire-damp at Newcastle. There are continual streams of it issuing from the coal seams or the accompanying strata. It mixes readily with ORDER I. PHOSPHOROUS HYDROGEN-GAS. 19 atmospheric air, in which state it has been the cause of many melancholy accidents by sudden explosions. 3. SULPHUREOUS HYDROGEN-GAS. Sulphuretted Hydrogen Gas. JAM. Man. p. 2. Schwe- felwasserstoffgas. HAUSM. I. S. 63. Amorphous. Transparent. Expansible. Sp. Gr. = 1-181. BERZ. 1-1912. GAY-LUSSAC. Odour of putrid eggs. OBSERVATIONS. 1. The sulphureous Hydrogen -gas consists of Hydrogen 5-824. Sulphur 94'176. BERZELIUS. It does not support combustion ; it blackens most of the metals, and becomes fatal to animals if inhaled in any consi* derable quantity. 2. It is developed from sulphureous waters, both cold and warm, as at Nenndorf, in "Westphalia, and at Baaden, near Vienna ; also from swamps and marshes. In Italy both cold and warm, it is disengaged from the soil of the Solfataras and of the Fumacchie, sometimes mixed with other kinds of gas, of which several instances have been mentioned by M. VON PRZYSTANOWSKY, in his Memoir on the Origin of the Vol- canoes in Italy. On the western bank of the Niagara river, a mile south of the Falls, it issues from the bank, which consists of a shelly limestone, including thin beds of coal and Iron-pyrites. Under similar circumstances, it occurs near Otsquaga Creek. A. EATON. 4. PHOSPHOROUS HYDROGEN-GAS. Phosphuretted Hydrogen Gas. JAM. Man. p. 2. Phos- phorwasserstoffgas. HAUSM. I. S. 64. Amorphous. Transparent. Expansible. Sp. Gr. = 0-9022. THOMSON. Odour of putrid fish. 20 PHYSIOGEAPHY. CLASS I. OBSERVATIONS. 1. This gas is composed of phosphorus and h}rdrogen, the relative quantities of which have not yet been ascertain- ed. Bubbles of this gas, passing through a liquid into atmospheric air, undergo a spontaneous combustion, and produce a smoke remarkable for its annular disposition. If allowed to remain for some time in contact with water, it imparts to it a disagreeable odour, and a bitter taste. 2. The phosphorous Hydrogen-gas, is the product of bogs and other humid places, which contain organic matter in a state of putrefaction. It has been considered as the cause of the ignis fatuus or jack o' lantern ; an opinion not very probable, if we compare the properties of the gas with the descriptions given of these luminous phenomena. GENUS II. ATMOSPHERIC-GAS. 1. PURE ATMOSPHEIIIC-GAS. Pure Atmospheric Air. JAM. Man. p. 2. Atmosphoe- rische Luft. HAUSM. III. S. 762. Amorphous. Transparent. Expansible. Sp. Gr. =: 1-0. It is nearly 800 times lighter than pure Atmospheric-water. OBSERVATIONS. 1. Pure Atmospheric-gas consists of Azote 78-999. Oxygen 21-000. Carbonic acid 0-001. BERZELIUS. The proportion of azote and oxygen is constant, that of carbonic acid is variable ; being sometimes higher, some- times lower than that mentioned above. Air filled in bottles at sea, at a considerable distance from the shore, has been found to contain no carbonic acid at all. 2. It constitutes the atmosphere, and surrounds the whole globe. ORDER II. PURE ATMOSPHERICXWATKIi. 21 ORDER 1 1. WATER. GENUS I. ATMOSPHERIC- WATER. 1. PURE ATMOSPHERIC-WATER. Pure Atmospheric "Water. JAM. Man. p. 3. Weich- Wasser. Hart-Wasser. HAUSM. III. S. 766. 773. Amorphous. Transparent. Liquid. Sp. Gr. := I'O. Without odour or taste. OBSERVATIONS. 1. Pure Atmospheric-water consists of Oxygen 88-94. Hydrogen 11 '06. BERZELIUS. In its natural state, it generally contains several earthy substances, salts, or acids, in a state of solution, which sometimes exercise a considerable influence upon its taste, odour, and specific gravity. Thus are formed the different kinds of hard water, of acidulous and bitter waters, and sea-water, which by some naturalists have been considered as particular species. If the temperature be sufficiently high or low, its form of aggregation is changed ; and in- stead of water, there appears steam or ice. The crystals of ice or snow, of which a great number are described and figured by Captain Scoresby, are commonly said to be- long to the rhombohedral system. But the figures of the crystals of snow, being commonly like that of a star with six radii, very nearly resemble the regular compositions of di- prismatic Lead-baryte, Kg. 38., and of other minerals belonging to the prismatic system. Dr BREWSTER has found, on the other hand, that ice exhibits in polarised light most distinctly the single system of coloured rings, depending tupon the existence of a single axis of double refraction. It will therefore be prudent to leave the question still undecided, to which system of crystalli- sation these forms belong, which will depend upon fu- PHYSIOGRAPHY. CLASS i. ture investigations of their angles. The grains of hail are compound, like other products of a similar formation. Those which fall during the changeable season of spring have the form of spheric sections, consisting of thin prisms, radiating from the centre, which prisms are co- lumnar particles of composition, and commonly opake. The hail formed during heavy thunder-storms, in general affects the shape of irregular, flattish globules; it is likewise compound, but often perfectly transparent, and including air bubbles. 2. The pure Atmospheric-water occurs in the shape of dew, mist, rain, snow, hail, ice, &c. ; also in springs, rivers, lakes, &c. In many instances it is found with admixtures of saline solutions, particularly in the sea. In the one or the other form, it is spread all over the globe. ORDER III. ACID. GENUS I. CARBONIC-ACID. 1. GASEOUS CARBONIC-ACID. Aeriform Carbonic Acid. JAM. Man. p. 4. Kohlensiiure. HAUSM. III. S. 792. Amorphous. Transparent. Expansible. Sp. Gr. = 1-51961. BIOT and ARAGO. Taste slightly acidulous, pungent. OBSERVATIONS. 1. The gaseous Carbonic-acid consists of Carbon 27'40. Oxygen 72'60. BERZELIUS. It suffocates animals, and extinguishes fire. It reddens the blue tincture of litmus ; but the original colour very soon returns. It produces a copious precipitate in a solution of quicklime in water; and is itself absorbed by water, to which it communicates its acidulous taste. ORDER III. GASEOUS SULPHURIC-ACID. 23 2. This acid is found most commonly in the neighbour- hood of, or stagnating upon, acidulous springs ; also in se- veral marshes, and in the solfataras. In various circum- stances it is formed upon the surface of the earth. It oc- curs in several excavations, both natural and artificial, as in the grotta del cane near Naples ; and in a cave in the Biidb's hegy, a porphyry mountain in Transylvania ; besides also in many mines, where in some places this dangerous gas is known by the name of Schwaden or Swath. The ga- seous Carbonic-acid, obtained by art, is employed for various purposes. GENUS II. MURIATIC-ACID. 1. GASEOUS MURIATIC-ACID. Aeriform Muriatic Acid. JAM. Man. p. 4. Salzsaure. HAUSM. III. S. 801. Amorphous. Transparent. Expansible. Sp. Gr. = 1-278 BERZ. 1-274} BIOT and ARAGO. Odour pungent. Taste strongly acid. OBSERVATIONS. 1 . The gaseous Muriatic-acid consists of Muriatic acid 75-31. Water 24-69. BERZELIUS. It is unfit for respiration, suffocates animals, and extin- guishes fire. The blue colour of an infusion of litmus is changed by it into a durable red one. 2. It occurs in the vicinity of active volcanoes, near Mount Etna and Vesuvius ; it is also said to be produced by stagnant waters in salt-mines. GENUS II. SULPHURIC-ACID. 1. GASEOUS SULPHURIC- ACID. Aeriform Sulphuric Acid. JAM. Man. p. 4. Schweflichte Saure. HAUSM. III. S. 797- 24 PHYSIOGRAPHY. CLASS I. Amorphous. Transparent. Expansible. Sp. Gr. = 2-247. BERZ. 2-1204. GAY-LUSSAC and THENARD. Odour pungent and acid, like that of burning sulphur. OBSERVATIONS. 1. The gaseous Sulphuric-acid consists of Sulphur 50-144. Oxygen 49-856. BERZELIUS. At the common temperature of our atmosphere it is per- manently elastic ; but it may be converted into a liquid substance, by exposing it to either frost or pressure. It is readily absorbed by water. 2. This acid rushes out from active volcanoes, and is found in considerable quantities, near Mount Etna, Vesu- vius, &c. It occurs likewise, along with gaseous Carbonic- acid, in a cave which is situated in the Biidb's hegy, a por- phyry hill in Transylvania, on the frontiers of Moldavia. At the foot of the mountain there are numerous acidulous springs, which develope a considerable quantity of gaseous Carbonic-acid. The walls of the cave described above, are covered with a crust of prismatic Sulphur. 2. LIQUID SULPHURIC-ACID. Liquid Sulphuric Acid. JAM. Man. p. 4. Schwefel- saure. HAUSM. III. S. 799. Acide sulfurique. HAUY. Tabl. comp. p. 1. Traitd de Min. 2de Ed. Tom. I. p. 295. Amorphous. Transparent, in different degrees. Liquid. Sp. Gr. = 1-857. BERZ. Taste strongly acid and burning. OBSERVATIONS. The anhydrous Sulphuric acid is solid, and consists of Sulphur 40-14. Oxygen 59-86. BERZELIUS. ORDER III. PRISMATIC BORACIC-ACID. 25 The liquid Sulphuric-acid contains at least 18-5 per cent, of water. If it contains 37 per cent, it possesses the pro- perty of crystallising at a temperature of 4° — 5° centigr., about 40° Fahr. The crystalline forms quoted are six-sided prisms terminated by six-sided pyramids, of which as yet neither the system nor the angles have been determined. 2. The liquid Sulphuric-acid occurs in the neighbour, hood of several volcanoes, as Mount Etna, and in great quantities in the island of Java, &c. ; it is found besides in caves in several places in Italy, and at Aix in Savoy. Sulphuric-acid is also formed by the decomposition of seve- ral species of the order Pyrites. GENUS IV. BORACIC-ACID. 1. PRISMATIC BORACIC-ACID. Sassoline or Native Boracic Acid. JAM. Syst. Vol. III. p. 48. Scaly Boracic Acid. Man. p. 5. Sassolin. HAUSM. III. S. 803. Boraxsaure. LEONH. S. 113. Acide bo- racique. HAUY. Tabl. comp. p. 2. Traite', 2de Ed. T. I. p. 297. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Determinable forms unknown. Lustre pearly. Colour greyish- and yellowish- white. Streak white. Feebly translucent. Sp. Gr. = 1480. BERZ. Taste acidulous, after- wards bitter and cooling, lastly sweetish. Compound Varieties. Loose scaly particles, crys- talline grains, sometimes aggregated in the form of crusts. OBSERVATIONS. I. The prismatic form of the six-sided tabular crystals 26 PHYSIOGRAPHY. CLASS i. of this substance has been inferred from Dr BREWSTER'S optical observations. 2. According to Professor STROMEYEH, the prismatic Boracic-acid from Volcano, one of the Lipari islands, is perfectly pure Boracic Acid, with an accidental admixture of sulphur. If pure, it consists of Boron 25-83. Oxygen 74-1 7« BERZELIUS. The crystallised variety contains 45 per cent, of water. It is fusible at the flame of a candle, and yields a glassy globule, which acquires resinous electricity by friction, even without being isolated. 3. It is deposited from the hot springs near Sasso, and from the lag&ni in Tuscany. Another locality is Volcano, one of the Lipari Islands. GENUS V. ARSENIC-ACID. 1. OCTAHEDRAL ARSENIC-ACID. Oxide of Arsenic. JAM. System. Vol. III. p. 552. Oc- tahedral Arsenic Acid. Man. p. 5. Arsenikbliithe. HAUSM. III. S. 805. Arsenikbluthe. LEONH. S. 170. Arsenic oxyde'. H AU Y. Traite', T. IV. p. 225. Tabl. comp. p. 108. Traite', 2de. Ed. T. IV. p. 241. Fundamental form, Hexahedron, Vol. I. Fig. 1. Simple forms. O, Vol. I. Fig. 2., commonly elon- gated in one or another direction. Cleavage octahedron, perfect. Fracture conchoidal. Colour white, often inclining to yellow. Streak white. Lustre vitreous, inclining to adamantine. Semi-transparent ... opake. Sp. Gr. = 3-698. ROGER and DUMAS. Taste sweetish astringent. ORDER IV. HEMI-PR1SMATIC NATRON-SALT. 27 Compound Varieties. Reniform, botryoidal, sta- lactitic ; thin crusts : particles of composition, if columnar, and very thin, commonly of a pearly lustre. Massive. Pulverulent. OBSERVATIONS. 1. The octahedral Arsenic-acid consists of Arsenic 75*82. Oxygen 24-18. BERZELIUS. If exposed to a high degree of temperature, it is entirely volatilised ; upon ignited charcoal it emits a strong garlick smelL Its white smoke condenses itself again upon cold bodies. It is soluble in water. The poisonous qualities of this substance are well known. 2. The repositories of the octahedral Arsenic-acid are the mineral veins, where it probably owes its existence to the decomposition of other minerals. It is chiefly accom- panied by native Arsenic, hemi-prismatic Sulphur, rhom- bohedral Ruby-blende, hexahedral Lead-glance, &c., and has been found at Audreasberg in the Hartz, at Joachims* thai in Bohemia, at Bieber in the principality of Hanau, &c. ORDER IV. SALT. GENUS I. NATRON-SALT. 1. HEMI-PRISMATIC NATRON-SALT. Prismatic Natron. JAM. Syst. Vol. III. p. 39. Man. p. 5. Natron. Carbonate of Soda. PHILLIPS, p. 190. Natiirlich Mineral- Alkali. WERNER. Hoffmann, Hand- buch. Th. III. 1. Abth. S. 212. Soda. Trona. HAUSM. III. S. 832. 833. Kohlensaures Natron. LEONH. -S. 614. Soude carbonate. HAUY. Traite', T. II. p. 373. TabL comp. p. 21. Traite', 2de. Ed. T. II. p. 207- Fundamental form. Scalene four-sided pyramid. P- {77! 14'}, 154° 3V, 115° 28'. Inclina- 28 PHYSIOGRAPHY. CLASS i. tion = 8° 0', in the plane of the long diagonal. Vol. I. Fig. 41. R. G. a : b : c : d = 19-10 : 3472 : 13-66 : 1. Simple forms. - (P) - 79° 41' ; (Pr + oo)3 (M) - 7fi° W . + Pr_ -f p i_ 3 ' - £ -163° 28'> ' 5' ; Pr -}- OD ; Pr + oo (7). Character of Combinations. Hemi-prismatic. In- clination of P — QD to ?r -f OD = 93° 0'. -p Combinations. 1. _. (fr + co)3. 2. ?. (Pr + OD)3. Pr + oo. Fig. 45. /v 3.?. Pr — 1. — ?5. (Pr + cc)3. Pr + o>. ft-S ?. (Pr + oo)5. Pr + oo. Pr + oo. ft Cleavage. — , distinct ; Pr + co imperfect ; traces si of (Pr + oo)3. Fracture conchoidal. Surface smooth and even. Lustre vitreous. Colour white, the grey and yellow tints are owing to foreign admixtures. Streak white. Semi-transparent. Sectile. Hardness = 1-0 ... 1-5. Sp. Gr. = 1-423. Taste pungent, alcaline. Compound Varieties. Several imitative shapes : composition columnar. Massive : composition gra- nular. Commonly occurring in the stale of powder. ORDER IV. PRISMATIC NATRON-SALT. 29 OBSERVATIONS. 1. The native carbonate of soda, found in the province of Sukena, in Africa, consists, according to KLAPROTH, of Soda 37'00. Carbonic Acid 38-00. Sulphate of Soda 2-50. Water 22-50. Its composition differs considerably from that of the crystallised varieties, to which the above description re- fers, the composition of these being expressed, according to BEHZELIUS, by Na C2 + 20 Aq = 21-77 of Soda, 15-33. of Carbonic acid, and 62-90 of Water. It is likely, therefore, to belong to another, perhaps to the following species. It is very soluble in water, effervesces with acids, and melts easily before the blowpipe. Blue vegetable colours are changed by it into green. 2. This salt loses its water, on being exposed to a dry atmosphere, and is therefore commonly met with in a state of efflorescent powder on the surface of the earth, on the shores of lakes, or in natural caverns. It is held in solution by certain mineral waters. According to BER- THOLET, it is formed in part by a decomposition of hexa- hedral Rock-salt, by carbonate of lime. 3. It occurs in considerable quantities in the plains of Debreczin, in Hungary ; also in Bohemia, Italy, and seve- ral other European countries, but principally in the soda lakes of Egypt, and in some parts of Asia and America. 4. Its chief employment is in the manufactures of soap. It enters also the composition of glass, and is used in dye- ing, washing, bleaching, &c. both in its natural state, and purified by the assistance of chemical processes. 2. PRISMATIC NATKON-SALT. Synonymes as above. Fundamental form. Scalene four-sided pyramid. P- 14-1° 48', 52° 9', 145° 52'. Vol. I.Fig.Q.Ap. SO PHYSIOGRAPHY. CLASS I. a : b : c = 1 : V0'806 : V 0-107- Simple forms. P— oo ; P (P) ; (Pr + <*>)5 (d) = 107° 50'; Pr— 1 = 121° 46'; ?r(o)=83° 50' ; Pr + OD (p). Char of Comb. Prismatic. Combinations. 1. P — oo. (?r -f oo)3. ]?r -f oo. 2. ?r. (Pr + )3. Pr -f cc. Similar to Fig. 9. 3. Pr. P. (Pr + ce)3. Pr + CD. Fig. 16. 4. P — QD. ?r — 1. Pr. P. (Pr+ce)3. Pr+cc. Cleavage, traces of Pr -|- OD, interrupted by conchoi- dal fracture. Imperfect. Fracture conchoidal. Surface generally smooth ; P — oo streaked, pa- rallel to its edges of combination with Pr. Lustre vitreous, more bright upon Pr -j- cc; the faces Pr — 1 and Pr being sometimes dull. Colour white, sometimes yellowish. Streak white. Trans- parent ... semi-transparent. Sectile. Hardness = 1-5. Sp. Gr. = 1-562. Taste pungent, alcaline. OBSERVATIONS. 1. The difference existing between this and the preceding species has hitherto remained unnoticed, although it seems that both of them are met with in nature. They may easily be obtained by the assistance of art, as have been the crys- tals of both species described above. If a perfectly satu- rated solution of carbonate of soda be exposed to a further evaporation at a temperature of about 25° — 40° centigr., about 77° — 104° Fah., or very slowly cooled, beautiful crys- tals of the prismatic species will be formed, whilst a less saturated solution will produce the hemi-prismatic species at a lower temperature, or if cooled more rapidly. 2. The relative chemical proportions of this salt have not ORDER IV. PRISMATIC GLAUBER-SALT. 81 yet been ascertained, if perhaps the above analysis by KLAF- ROTH does not belong to the present species. It seems to differ from the hemi-prismatic Natron-salt, chiefly by its containing a smaller quantity of water. It is, like the for- mer, subject to decomposition, by which it loses its water, and is reduced to a powder ; yet this effect does not take place so easily and so quickly, as in the hemi-prismatic species. If they are both contained in the carbonate of so- da of commerce, the crystals of prismatic Natron-salt are very often found to be quite fresh in the drusy cavities, while those of the hemi-prismatic, are already entirely de. composed. GENUS II. GLAUBER-SALT. 1. PRISMATIC GLAUBEE-SALT. Prismatic Glauber Salt. JAM. Syst. Vol. III. p. 31. Man. p. 7. Glauber Salt. Sulphate of Soda. PHIL. p. 191. Naturlich Glaubersalz. WERN. Hoffm. H. B. Th. III. 1. S. 245. - Glaubersalz. HAUSM. III. S. 835. Schwefelsaures Natron. LEONH. S. 617, Soude sul- fate'e. HAUY. Tabl. comp. p. 19. Traite, 2de. Ed. T. II. p. 189. HAIDINGER. Edinb. Phil. Journ. No. XX. p. 305. Fundamental form. Scalene four-sided pyramid. p = ISP io'} ; uo° 23/ ; 105° 6K Inclina- tion = 14° 41' in the plane of the long diagonal. Vol. I. Fig. 41. R. G. a : b : c : d = 3-816 : 7'005 : 3-188 : 1. c« If T> /A jP f " 1 f 93° 12' 1 Simple forms. P— Gc(Z); ± - | z | = | 81o 10. |; PHYSIOGRAPHY. CLASS I. _ J 49°50'. f r + 1 _o,. ~ Pr-f oo(J/); Pr— !(?/) — 118° 12'; Pr 4- oo(P)- Char, of Comb. Hemi-prismatic. Inclination of P— GO to Pr 4- GO = 104° 41'. Pr P - Combinations. 1. — - — — — .(fr-f x)3.Pr4- oo. *v /C 2. _. — _f. — _. (fi-4- •&«, T> JJy. I 1 8. ±. — _. — i. — £!l±-f . (f r 4- «))5. 222 2 Pr 4- oo. Pr 4- cc. 4.P-oo.?-r. ?. pr_l._!r-?. o Q 22 - (Pr)3 .?r_t_l. - 2 2 ?r 4- co. Pr 4- GO. Fig. 56. Cleavage, f r 4- oo, highly perfect, and easily ob- tained ; traces of — — and of Pr 4- oo. Frac- 2 ture conchoidal, perfect. Surface smooth and even, alike in all the forms. Lustre vitreous, bright. Colour white. Streak white. Transparency perfect. Sectile. Hardness = 1-5 . . . 2-0. Sp. Gr. = 1-481. Taste cool, then saline and bitter, feeble. Compound Varieties. Twin- crystals : face of composition parallel to Pr 4- GO ; axis of revolu- tion perpendicular to Pr 4- GO. Rare. Several imi- tative shapes. Efflorescent. Mealy crusts. ORDER IV. PRISMATIC GLAUBER-SALT. 33 OBSERVATIONS. 1. The crystals obtained while the solution of sulphate of soda is cooling, are in most cases lengthened in the di- rection of the edges between M and 71, as in Fig. 55. ; and implanted in the place of the face P. Those which are formed duringp a slow evaporation are solitary, and limited by a greater number of faces, as in the crystal represented in Fig. 56. 2. The chemical formula of prismatic Glauber-salt is Na 8*2 + 20 Aq. = 19-39 of Soda, 24-85 Sulphuric Acid, and 55-76 Water. It is easily soluble in water, but decom- poses readily on being exposed to the air, and falls into powder. It is thus found in nature ; a variety from Egra, in Bohemia, has yielded to REUSS, Sulphate \ < 67'024. Carbonate [-of Soda -< 16-333. Muriate ) 1 11-000. Muriate of Lime 5-643. The progress of decomposition of this species is very pecu- liar ; it takes its rise from single points, which enlarge and extend in several directions, while the rest of the crystal remains in its original state : so that the whole takes the appearance of worm-eaten wood. It is possible also to obtain crystals of the anhydr&u$ Glauber-salt, if a solution of sulphate of soda be evapo- rated at a temperature above 33° centigr., above 106° Fahr. The crystals are prismatic, of the form P. P + «. Pr + «, similar to Fig. 6. ; more commonly they shew only the pyramid P, Vol. I. Fig. 9., whose angles have not yet been ascertained. They are easily cleavable in the di- rection of Pr + co. Their hardness is = 2-5, their specific gravity = 2-462. They are white and transparent, but become very soon opake, if exposed to a higher tem- perature. 3. The prismatic Glauber-salt is found in nature accom- panying hexahedral Rock-salt and prismatic Epsom-salt, or as an efflorescence upon the soil and several rocks, also on the shores of salt lakes, and in some mineral springs. VOL. II. C 34 PHYSIOGRAPHY. CLASS i. 4. It occurs in the neighbourhood of Aussee, Ischel, and Hallstadt in Austria, at Hallein in Salzburg, in Hun- gary, in Switzerland, also in Italy and Spain. 5. It is employed in medicine, and in manufacturing GENUS III. NITRE-SALT. 1. PRISMATIC NITRE-SALT. Prismatic Nitre. JAM. Syst. Vol. III. p. 35. Man. p. 8. Nitre. Nitrate of Potash. PHILLIPS, p. 189. Naturli- cher Salpeter. WERN. Hoffm. H. B. Th. III. 1. S. 216. Salpeter. HAUSM. III. S. 849. Salpeter. LEONH. S. 629. Potasse nitrate'e. HAUY. Traits', T. II. p. 346. Tabl. comp. p. 19. Trait^, 2de. Ed. T. II. p. 177. Fundamental form. Scalene four-sided pyramid. P = 132° 22'; 91° 15'; 107° 43'. Vol. I. Fig. 9. HAUY. a : b ; c = 1 : V 2'1333 : V 0-7H1- Simple forms. P — co (o) ; P — 1 (z) ; P (y) ; P + 1 (t) ; P + oo (M) = 120° ; f r (x) - 111° 12'; P r + 1 (P) = 72° IT; P r + 2 (*) = 40° 7'; £r + o>W; Pr + oo (/)• Char, of Comb. Prismatic. Combinations. 1. Pr+ 1. P + QD. £r + oo. Fig. 9. 2. P. Pr+1. P+oo. fr + oo. 3. P — co. p r + 1. P+oo. Pr + QD. 4. £r. £ + 1. Pr + 2. P + co. Pr+cc. Fig.23. Cleavage, P + co and f r + oo. Imperfect, the latter rather more easily observed than the former. Fracture conchoidal, Surface, P + QD and Pr -f- GO striated, both horizontally and vertically, particu- larly in irregular crystals. ORDER IV. PRISMATIC NITRE-SALT. 35 Lustre vitreous. Colour white. Streak white. Transparent ... semi-transparent. Sectile. Hardness = 2-0. Sp. Gr. = 1-9369. HASSENFRATZ. Taste saline and cool. Compound Varieties. Twin-crystals, very fre- quent, compound parallel to one or both the faces of P + OD, variously repeated, similar to Fig. 39. In crusts and flakes : composition sometimes co- lumnar. OBSERVATIONS. 1. The prismatic Nitre-salt, as it is found at the Pulo di Molfetta, in Apulia, consists, according to KLAPROTII, of Nitrate of Potash 42-55. Sulphate \ f 25-45. Muriate I of Lime •< 0-20. Carbonate J 130-40. The composition of the crystals is expressed by K N2 = 55-28 of Potash and 44-72 Nitric acid. It dissolves very easily in water, is not altered on being exposed to air, and detonates with combustible substances. 2. More commonly this salt occurs in thin crusts on the surface of the earth, sometimes upon limestone, chalk, or calcareous tufa ; also in caves contained in limestone, and mixed up with, or in small veins traversing, sandstone. 3. Spain, Italy, and Hungary, afford considerable quan- tities of this salt. In still greater proportions, and in a high state of purity, it is met with in India, and in several caverns in limestone, and in the sandstone of the United States of North America. 4. Its chief employment is in the composition of gun- powder. Besides this, it is used in medicine, for obtain- ing nitric acid, and for several other purposes. In some countries, as in the East Indies, in Spain, and in Hun- gary, it is collected for use ; the greater part of that, which 36 PHYSIOGRAPHY. CLASS 1. is an object of commerce, is extracted from heaps, gather- ed together for that purpose. GENUS IV. ROCK-SALT. 1. HEXAHEDRAt ROCK-SALT. Hexahedral Rock-Salt. JAM. Syst. Vol. III. p. 1. Man. p. 9. Common Salt. PHILL. p. 193. Naturlich Kochsalz. WERN. Hoffm. H. B. Th. III. 1. S. 222. Steinsalz. HAUSM. III. S. 843. Steinsalz. LEONH. S. 619. Soude muriatee. HAU r. Traite', T. II. p. 356. Tabl. comp. p. 20. Traite', 2de. Ed. T. II. p. 191. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (P) ; 6 (o) Vol. I. Fig. 2. ; D. Vol. I. Fig. 31.; A*. Vol. I. Fig. 32. Character of Combinations. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4. 2. H. A«. Fig. 152. 3. H. D. As. 4. H. O. A*. Cleavage^hexahedron, perfect. Dodecahedron, often distinct, though generally only a few faces. Fracture conchoidal. Surface generally smooth ; the faces of the icositetrahedron sometimes rough. Lustre vitreous, somewhat inclining to resinous. Colour, generally white, passing into yellow, flesh-red and ash-grey. Sometimes beautifully violet-, berlin-, or azure-blue. Streak white. If scratched with the nail it does not yield any powder, but receives an impression, and becomes a little shining. Transparent ... translucent. Rather brittle. Hardness = 2-0. Sp. Gr. =r 2-257, a yellowish-white transparent variety. Taste saline. ORDER IV. HEXAHEDRAL ROCK-SALT. 37 Compound Varieties. Dentiform and some other imitative shapes, rare. Commonly massive. Com- position* granular or columnar, the latter in most cases parallel, sometimes curved. Size of the com- ponent individuals various. Faces of composition rough. OBSERVATIONS. 1. The species of hexahedral Rock-salt has formerly been divided into different sub-species and kinds. The principles, according to which this sub-division has been effected, are the geognostic relations and the mechanical composition of its varieties, and therefore not founded upon Natural History. Thus the varieties occurring in beds, have been called Rock-salt ; such as are formed at the bot- tom of salt lakes, or on their shores, Sea-salt ; and the for. mer again have been divided into foliated and fibrous Rock- *alt, according to their granular or columnar mode of com- position. 2. The hexahedral Rock-salt consists of Muriate of Soda 983-25. Sulphate of Lime 6-50. Muriate of Magnesia 0-19. Muriate of Lime 0-06. Undissolved Matter 10-00. HENRY. The composition of the Muriate of Soda is expressed by Na M3 = 53-29 of Soda, and 46-71 Muriatic acid. It is very easily soluble in water, remains unaltered if exposed to the * A remarkable kind of composition on a large scale has been long ago known to occur in the Rock-salt of Cheshire. Concentric layers of this substance, of different colours and purity, alternate with each other, and produce globular masses of a diameter of several yards. Several of these globular masses are again enveloped in concentric layers, common to them all, in a manner exactly analogous to the composition observable on a small scale in Pearlstone, a variety of empyrodox Quartz. 38 PHYSIOGRAPHY, CLASS I. dry atmosphere, and decrepitates upon glowing charcoal, or before the blowpipe. It crystallises, both from solutions in water, and from fusion. It undergoes a remarkable change if exposed to a moist atmosphere, from which it attracts a por- tion of water. The dissolution of a mass of a hexahedral shape begins regularly at its edges, and transforms this first into a combination of the hexahedron and the hexahedral trigonal-icositetrahedron, Fig. 152., and then into a simple form of that kind, without any additional faces, Vol. I. Fig. 32. In the latter form, the mass of the salt diminishes in size, till at last it is entirely dissolved. 3. The hexahedral Rock-salt occurs chiefly in beds, some of which are of considerable dimensions, though commonly of a rather irregular form, and is met with in secondary, according to some geologists also in transition rocks, accompanied by both the species of Gypsum-haloide, principally the prismatoidal one, by several compound va- rieties of rhombohedral Lime-haloide, associated with sand- stone, clay, &c. It is likewise found at the bottom, and in the vicinity of salt lakes, in the waters of which it is dis- solved. It is contained in the waters of salt springs, of several mineral wells, and of the sea, though in variable quantities. It occurs upon certain varieties of lava, and in some volcanic lakes. 4. Hexahedral Rock-salt is found in considerable quan- tity in Poland, Hungary, Transylvania, Moldavia, and Valachia, in Stiria, Upper Austria, Salzburg, the Tyrol, Bavaria, Wurtemberg, and Switzerland ; also in England, in Spain, and in many other countries in and out of Eu- rope. In several of these, and in some others, where this salt has never been found in a solid state, there occur nevertheless a number of salt-springs, from which it may be obtained by means ef evaporation. The sea-salt in par- ticular is found in the Crimea, in the deserts at the Cas- pian Sea, in Egypt, and in several places in Southern Afri- ca and America. 5. The employment of hexahedral Rock-salt for culinary purposes, in different arts and manufactures, &c. is too ORDER IV. OCTAHEDKAL AMMONIAC-SALT. 89 well known to be mentioned here more at large. It shall only be remarked, that for the greater part it is not used in the state in which it is found in nature, but in that in which it is obtained from evaporating its solutions. GENUS V. AMMONIAC-SALT. 1. OCTAHEDRAL AMMONIAC-SALT. Octahedral Sal Ammoniac. JAM. Sjst. Vol. III. p. 11. Man. p. 11. Muriate of Ammonia. PHILL. p. 194. Naturlicher Salmiak. WEEN. Hoff. H. B. Th. III. 1. S. 219. Salmiak. HAUSM. III. S. 853. Salmiak. LEON H. S. 631 . Ammoniaque muriate'e. HAU Y. Traits', T. II. p. 360. Tabl. comp. p. 22. Traite7, 2de Ed. T. II. p. 221. Fundamental form. Hexahedron. Vol. I. Fig, 1. Simple forms. H; 6(P), Vol. I. Fig. 2.; D,Vol. I. Fig. 81. ; C i (*), Vol. I. Fig. 34. Char, of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4. Cleavage, octahedron. Fracture conchoidal. Sur- face smooth. Lustre vitreous. Colour generally white, often inclining to yellow or grey. Sometimes it is stained green, yellow, or black. Transparent ... translucent. Very sectile. Hardness = 1-5 ... 2-0. Sp. Gr. = 1-528. Taste acute and pungent. Compound Varieties. Stalactitic, botryoidal, glo- bular, reniform shapes, also in crusts : composition columnar. Massive: composition impalpable. Frac- ture conchoidal. Sometimes in a state of mealy efflorescence. 40 PHYSIOGRAPHY. CLASS i. OBSERVATIONS. 1. The octahedral Amnioniac-salt from Mount Vesuvius consists of Muriate of Ammonia 99'5. Muriate of Soda 0-5. KLAPROTH. In its pure state it is N H6 M2 + Aq = 32-06 of Am- monia, 51-16 Muriatic acid, and 16-78 Water. It is perfectly volatile at a higher temperature, dissolves readily in water, but does not attract moisture from the atmosphere. It emits a pungent smell of ammonia, if rubbed wet with quicklime. If a saturated solution of this salt be brought into a lower temperatiire, its surface will very soon be covered with feathery masses of aggregated crystals, which sink to the bottom, when they have attained a certain weight. The movement thus produced in the fluid gives rise to the for- mation of numerous small crystals, terminated on all sides, which appear to consist of three needles perpendicular to each other, or as it were the pyramidal axes of the octahe- dron, whenever they become large enough to be visible by the assistance of a microscope. In the beginning they are quite steady in the fluid, but they sink when they increase in weight, during which their size also continually increases. The continuation of this process, and the more rapid cool- ing of the outer parts of the fluid, produce a regular move- ment within the latter, since the colder particles sink, while the warmer rise in its centre, and carry along with them part of the crystals already formed. This movement again accelerates the formation of the crystals, the fluid appears now quite troubled, and does not become clear again, till whatever had been dissolved in the fluid above its capacity at that temperature, has fallen to the bottom of the vessel in the shape of highly delicate flakes of snow. MONGE seems to be the first who described this pheno- menon. Crystals of considerable size are obtained by sub- limation. It must be observed here, that the tessular form of the crystals of this substance is given upon the authority of ORDER IV. HEMI-PRISMATIC VITRIOL-SALT. 41 HAUY and others. The shape which the small crystals as- sume when forming in the fluid, seems rather to indicate the pyramidal system, particularly if compared to the figure given by Mr PHILLIPS, which represents the icositetrahe- dron Ci, having only four of its unequiangular solid angles replaced by additional faces, so that those faces by them- selves would produce a rectangular four-sided prism. 2. The octahedral Ammoniac-salt occurs in cracks and fissures in the immediate vicinity of active volcanoes, and is a product of sublimation. Thus it is also found near burning coal-seams. It has been said to occur in slaty clay along with prismatic Sulphur. 3. Its best known localities are Mount Etna and Ve- suvius, the Solfataras, the Lipari islands, England, par- ticularly the neighbourhood of Newcastle, Scotland, Ice- land, the neighbourhood of Liege, the Buchanan Tartary, &c. It is often produced by immediate composition of its constituent parts, or by various chemical processes. A considerable quantity is produced in Egypt by the combus- tion of the dung of camels. 4. This salt, as it occurs in nature, will probably be of very little use, on account of its scarcity. That obtained by the assistance of art is employed in dyeing, in medicine, and in several operations of metallurgy. GENUS VI. VITRIOL-SALT. 1. HEMI-PRISMATIC VITRIOL-SALT. Rhomboidal Vitriol or Green Vitriol. JAM. Syst. Vol. III. p. 17. Hemi-prismatic Vitriol or Green Vitriol. Man. p. 13. Sulphate of Iron. PHILL. p. 240. Natiirlicher Vitriol. WERN. Hoffm. H. B. Th. III. 1. S. 235. Eisenvitriol. HAUSM. III. S. 1058. Eisen- Vitriol. LEONH. S. 355. Fer sulfate. HAUY. Trait^, T. IV. p. 122. Tabl. comp. p. 100. Traite', 2de Ed. T. IV. p. 140. Fundamental form. Scalene four-sided pyramid. 42 PHYSIOGRAPHY. CLASS I, P =r { l^°0 ^ } ; 108° 6' ; 126° 58'. Inclina- tion of the axis = 14° 20' in the plane of the long diagonal. Vol. I. Fig. 41. R. G. a : b : c : d = 3-920 : 3-090 : 2-629 : 1. Simple forms. P — o> (6) ; ? (P) = 101° 35' ; -69°6'- +^r ° / ±- -- l - - 128° 4' Pr (o) = 69° IT ; Pr + (M). Char, of Comb. Hemi-prismatic. Inclination of P — OD to ?r + QD = 104° 20' ; of P — QD to P + oo = 99° 23'. Combinations. 1. P — oo. P -f oo. Sim. Fig. 44. 3. P — QD. — — . Pr. P + QD. Pr + QD. Pr -f oo. 4 P - a,. L^Z^ Lr. ?. Pr. - ?_r. 222 2 P + x. Pr 4- CD. Fig. 52. Cleavage. P — OD, perfect ; P + oo, distinct, though less perfect than P — QD ; sometimes traces of — —. Fracture conchoidal. Surface generally smooth ; nearly the same in all the forms. Lustre vitreous. Colour, several shades of green, passing into white. Streak white. Semi-trans- ORDER IV. HEMI-PRISMATIC VITRIOL-SALT. 43 parent ... translucent. A faint blueish opales- cence sometimes observable parallel to the faces of Pr + QD. Rather brittle. Hardness = 2-0. Sp. Gr. = 1-832, of a variety containing about 0-1 of sulphate of copper. Taste sweetish -astringent and metallic. Compound Varieties. Stalactitic, botryoidal, re- niform : composition columnar ; if the particles be- come very thin, the lustre approaches to pearly. Massive : composition granular. Pulverulent. OBSERVATIONS. 1. The present species consists of Oxide of Iron 25-7- Sulphuric Acid 28-9. Water 45-4. BERZELIUS. It is Fe 8*2 + 12 Aq = 26-19 Oxide of Iron : 29-89 Sul- phuric Acid : 43-92 Water, according to MITSCHERLICH. It is easily soluble in water, and the solution becomes black on being mixed with tincture of galls. If exposed to the open air, it soon becomes covered with a yellow powder, which is Persulphate of Iron. Before the blowpipe it be- comes magnetic, and colours glass of borax green. 2. In most cases the hemi-prismatic Vitriol-salt is pro- duced by the decomposition of other minerals, particularly of hexahedral and prismatic Iron-pyrites ; and it is there- fore commonly found in such places in which artificial heaps constructed for that purpose, mines or other circum- stances, have given occasion to its formation. It is also found dissolved in the waters of several mines. 3. It occurs in the Rammelsberg near Goslar in the Hartz, at Schwarzenberg in Saxony, in several mines at Schemnitz in Hungary ; also in Sweden, in Spain, &c. ; in different coal-mines in England ; at Hurlet in Renfrew- shire in Scotland, and other places. 4. Both the natural and the artificial hemi-prismatic Vi- 44 PHYSIOGRAPHY. CLASS X. triol-salt, are used in dyeing, in making ink and Prussian blue, and also for producing sulphuric acid. The residue from the distillation, being red oxide of iron, is employed as a colour, and for polishing steel. 2. TETARTO-PRISMATIC VITRIOL-SALT. Prismatic Vitriol, or Blue Vitriol. JAM. Syst. Vol. III. p. 19. Man. p. 14. Sulphate of Copper. PHILL. p. 313. Natiirlicher Vitriol. WERN. Hoffm. H. B. Th. III. 1. S. 235. Kupfervitriol. HAUSM. III. S. 1054. Kup- fer- Vitriol. LEONH. S. 271. Cuivre sulfate'. HAUY. Traite', T. III. p. 580. Tabl. comp. p. 92. Traite', 2de Ed. T. III. p. 523, Fundamental form. Scalene four-sided pyramid of unknown dimensions. Inclination of the axis in the planes of both diagonals. Vol. I. Fig. 42. Simple forms, not determined. Char, of Comb. Tetarto-prismatic. Cleavage, very imperfect in the direction of the faces T and M, Fig. 83., the latter rather more distinct. Fracture conchoidal. Surface: the faces n commonly deeply striated, parallel to their edges of combination with M and T9 which faces are also sometimes striated, though not so generally as n. Lustre vitreous. Colour, sky-blue, in different shades, commonly deep. Streak white. Semi- transparent ... translucent. Rather brittle. Hardness = 2-5. Sp. Gr. = 2-213. Taste astringent and metallic. OBSERVATIONS. 1. The theory of the forms in which the inch* nation of the axis takes place at the same time in the planes of both diagonals, has not as yet been perfectly developed. In OBDER IV. TETABTO-PBISMATIC VITRIOL-SALT. 45 the present place it seems to be the best, to describe one of the varieties most generally occurring, together with the angles as given by HAUY, in order to enable the stu- dent to compare this crystal with others he should meet with in nature. This variety is represented Fig. 83. The incidence of P to M is = 109° 32'; of P to T = 128° 27'; ofM to T = 149° 2'; of « to T = 149° 42"; of r to M = 126° 11'; of r to T = 109° 47'; of u to P = 126° 11'; of u to M = 124° 17'. of n to M = 154° 2(K; 2. The tetarto-prismatic Vitriol-salt consists of Oxide of Copper 32-13. Sulphuric Acid 31-57. Water 36-30. BERZELIUS. It is Cu S2 + 10 Aq = 29-9 Oxide of Copper : 32-3 Sulphuric Acid : 37*8 Water, according to MITSCHEH- LICH. Very often sulphate of copper is contained in dif- ferent proportions in the crystals of hemi-prismatic Vitriol- salt ; the forms of the latter nevertheless are not affected by this admixture, except that they more commonly pre- sent the simple varieties, as, for instance, that of Fig. 44. It is easily soluble in water, and gives a blue solution. A polished surface of iron is covered with a film of metallic copper, if dipped into this solution. 3. This salt, like the preceding one, owes its existence to the decomposition of other minerals, particularly of py- ramidal Copper-pyrites, and is often produced by various chemical processes. It is found dissolved in several wa- ters, partly issuing from mines, and which have received the name of waters of Cementation. 4. Its chief localities are the Rammelsberg near GosJar, Neusohl in Hungary, Anglesea in England, Wicklow in Ireland, Fahlun in Sweden, the isle of Cyprus, &c. 5. As it occurs in nature, it requires first to be puri- fied, before it can be employed in the arts, where it is used in dyeing, in printing of cotton and linen, &c. The oxide of copper, separated from its acid, is likewise used in painting. 46 PHYSIOGRAPHY. CLASS 1. G. The salt which goes by the name of Blue Vitriol from Goslar, though it contains sulphate of copper, is not tetar- to-prismatic Vitriol-salt, since its forms are not tetarto- prismatic, but hemi-prismatic, and similar to those of the hemi-prismatic Vitriol-salt. Its colour is sky-blue, but considerably paler than that of tetarto-prismatic Vitriol- salt. Besides sulphate of copper, it also contains sulphate of zinc, and is probably one of the salts expressed by the general formula 11 S2 + 12 Aq. of MITSCHERLICH, upon which supposition it would consist of 14-95 Oxide of Copper, 13-83 Oxide of Zinc, 29-94 Sulphuric Acid, and 41-28 Water. 3. PRISMATIC VITRIOL-SALT. Pyramidal Vitriol or White Vitriol. JAM. Syst. Vol. III. p. 21. Man. p. 75. Sulphate of Zinc. PHILL. p. 356. Natiirlicher Vitriol. WEEN. Hoffm. H. B. Th. III. 1. S. 235. Zink- Vitriol. HAUSM. III. S. 1118. Zink- Vitriol. LEONH. S. 314. Zinc sulfate. HAUY. Traite', T. IV. p. 180. Tabl. comp. p. 104. Trait*?, 2de Ed. T. IV. p. 198. Fundamental form. Scalene four-sided pyramid. P = 127°27'; 126°45'; 78°5'. Vol.1. Fig.9. R.G. a : b : c = 1 : V 3-0407 : V 3-0037. Simple forms. P (1) ; P + oo (M) = 90° 42' ; (Pr)3 ; (Pr + . IPr + oo. Fig. 6. 3. Pr. Pr. P. P + oo. Pr -f- oo. 4. Pr. P. P + oo. (?r + oo)3. £r + oo. Cleavage, Pr + oo highly perfect; Pr, less dis- tinct; traces of P -|- oo. Fracture conchoidal. Surface. P + oo sometimes, Pr + oo almost al- ways vertically streaked. The rest of the faces smooth and even. Lustre vitreous. Colour white. Streak white. Transparent ... translucent. Rather brittle. Hardness = 2-0 ... 2-5. Sp. Gr. = 1*751. Taste saline and bitter. Compound Varieties. Botryoidal, reniform, and in the shape of crusts : composition columnar, if ORDER IV. PRISMATIC EPSOM-SALT. 4 the particles are very delicate, the lustre becomes pearly. Pulverulent. OBSERVATIONS. 1. In the combinations occurring among the crystals of this species, some of the faces of the pyramid P (I) are very often irregularly enlarged at the expence of others. Since this enlargement sometimes takes place in the alternating faces of the pyramid, it has been supposed by several crys- tallographers, and among others by Messrs HAUY and WEISS, to follow a certain constant rule. Considering the vertical prism as rectangular, and completing what otherwise might have been wanting in the forms, they have thus re- presented the series of crystallisation of prismatic Epsom- salt as being hemi-pyramidal with inclined faces, a supposi- tion rendered sufficiently improbable, as far as regards the pyramidal system, if we only attend to the position of the single perfect face of cleavage. Professor MITSCHERLICH, however, has lately observed, that of some secondary faces, as *, *, and £, £, which belong to (Pr)3 and (Pr)3, only the alternating ones appear in the combinations, as represented in Fig. 1G8. ; and according to this observation, the Cha- racter of Combinations has been stated above as hemi-pris- matic with inclined faces.* 2. According to VOGEL, the prismatic Epsom-salt con- sists in its natural state of Water 48-0. Sulphuric Acid 33-0. Magnesia 18'0. It is Mg s'2 4- 14 Aq, or 16-6 Magnesia, 32-2 Sulphuric acid, and 51'2 Water, according to MITSCHERLICH. It dissolves very easily in water, deliquesces before the * Professor Mitscherlich has kindly communicated to me this interesting fact, which he has likewise observed in pris- matic Vitriol-salt, and in the crystals of sulphate of nickel. H. 50 PHYSIOGRAPHY. CLASS i. blowpipe, hut is difficultly fusible, if its water of crystalli- sation has been driven off. 3. It effloresces from several rocks, both in their original repository, and in artificial walls, and then it is a product of their decomposition. It forms the principal ingredient of certain mineral waters. 4. It occurs in Freiberg and in its neighbourhood efflo- rescent upon gneiss, in several places of the Hartz, in Scotland, in Berchtesgaden, in Salzburg, at Idria in Car- niola, from whence it has been described under the name of Halotrichum, or Hair-salt, in Bohemia, in Hungary, &c. 5. After having been purified, it is employed in medi- cine, as also for the production of magnesia. GENUsVIII. ALUM-SALT. 1. OCTAHEDRAL ALUM-SALT. Octahedral Alum. JAM. Syst. Vol. III. p. 27. Man. p. 17. Alum. PHILL. p. 196. Alaun. Hoffiii. H. B. Th. IV. 2. S. 169. Alaun. HAUSM. III. S. 813. Alaun. LEONH. S. 625. Alumine sulfate'e alcaline. HAUY. Trait^, T. II. p. 387. Tabl. comp. p. 22. Alumine sulfate'e. Traite, 2de. Ed. T. II. p. 114. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (r); 6 (P) Vol. I. Fig. 2. ; D (o) Vol. I. Fig. 81. ; B Vol. I. Fig. 33. ; Ci Vol. I. Fig. 34. Char, of Comb. Semi-tessular with parallel faces. Combinations. 1. H.O. Vol. I. Fig. 3. and 4. 2. H. O. D. 3. ILO. D. B. Ci. Cleavage, octahedron, imperfect. Fracture con- choidal. Surface smooth. The faces of the ORDER IV. OCTAHEDRAL ALUM-SALT. 51 dodecahedron sometimes faintly streaked, parallel to its edges of combination with the octahedron. Lustre vitreous. Colour white. Streak white. Transparent ... translucent. Not very brittle. Hardness = 2-0 ... 2-5. Spec. Grav. = 1-753, of a transparent variety. Taste sweetish astringent. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendi- cular to one of the faces of the octahedron. Sta- lactitic and other imitative forms : composition co- lumnar, if they are very delicate the lustre becomes pearly. Massive : composition either columnar or granular, often impalpable. Mealy efflorescence. OBSERVATIONS. 1. The Character of Combinations is given on the autho- rity of Count BOURNON and M. BEUDANT. According to BEUDANT, certain combinations obtained by dissolving Alum in muriatic-acid, and allowing it to crystallise, contain the faces of a pentagonal dodecahedron, which is the half of a hexahedral trigonal-icositetrahedrou. Count BOURN ON like- wise quotes this variety as having been obtained by himself. 2. KLAPROTH having analyzed a variety from Freien- walde hi Silesia, called natural alum, but which probably does not belong to this species, obtained the following result : Alumina 15-25. Potash 0-25. Oxide of Iron 7-50. Sulphuric Acid and Water 77*00. The crystallized varieties to which the above description refers, are K S2 + 2 Al S* + 48 Aq, or 9'94 Potash, 10'82 Alumine, 33*77 Sulphuric acid, and 45-47 Water. It is pretty easily soluble in water, melts before the blow- PHYSIOGRAPHY. CLASS I. pipe in its water of crystallisation, and is converted into a spongiform mass. 3. The octahedral Alum-salt commonly appears in a state of efflorescence upon several minerals, which contain alu- mina, as upon rhombohedral Alum-haloide, alum-slate, alum- earth, &c. : but it occurs also in a solid shape accompany- ing brown-coal, and is contained in the waters of certain mineral wells. 4. It is found in several parts of Italy. At Tschermig near Kommothau in Bohemia, it forms thin layers between the strata of brown-coal. It is likewise met with at Freien- walde in Silesia, in England and Scotland, in Norway, Sweden, &c. 5. The salt as produced by nature requires first to be purified, in order to be applicable in the arts. A great quantity is obtained by the assistance of chemical processes. Its uses are various, in dyeing, in manufacturing leather and paper, for preventing putrefaction, &c. GENUS IX. BORAX-SALT. 1. PRISMATIC BORAX-SALT. Prismatic Borax. JAM. Syst. Vol. III. p. 45. Man. p. 18. Borate of Soda. PHILL. p. 192. Tinkal. HAUSM. III. S. 841. Boraxsaures Natron. LEONH. S. 623. Soude borate'e. HAUY. Traite, T. II. p. 366. Tabl. comp. p. 20. Traite', 2de Ed. T. II. p. 200. Fundamental form. Scalene four-sided pyramid. P = 152° 9', 120° 23', 67° 3'. Inclination = 0° 0', in the plane of the long diagonal. Vol. I. Fig. 41. HAUY. a : b : c : d = 1 : 12 : *W125 : 0. Simple forms. ? (o) = 120° ORDER IV. PKISMATIC BOKAX-SALT. 53 (Pr + o>)5 (r) = 88° 9' ; — — (P) = 73° 54' Pr + OD (Jl/) ; Pr + OD (T). Char, of Comb. Hemi-prismatic. Combinations. 1. — _. (Pr + ao)5. Pr + oo. . Pr+a>. 3. . — . Pr + oo. Pr + x. . . . Pr -|- oo. Fig. 51. Cleavage, f r -f- oo, perfect ; less distinct (Pr -J- oo) 3 ; traces of Pr + oo. Fracture conchoidal. Sur- face of ?, (—j)l and (Pr + oo)5 streaked pa- nl 2 rallel to the edges of combination with — -5. Jl The rest of the faces smooth. Lustre resinous. Colour white, inclining to grey and green. Streak white. Transparent . . . translucent. Rather brittle. Hardness = 2-0... 2-5. Sp. Gr. = 1'716. Taste sweetish alcaline, feeble. OBSERVATIONS. 1. The natural borax consists, according to KLAPBOTH, of Soda 14-5. Boracic-Acid 37-0. Water 47-0. 54 PHYSIOGRAPHY. CLASS i. This composition corresponds to the formula Na 15 8 + 24 Aq. The preceding general description, however, refers to the artificial salt, which is expressed by Na B2 + 10 Aq, and consists of 31-97 Soda, 22-06 Boracic acid, and 45-97 water. It is soluble in water ; the solution changes the blue colour of litmus into green. It intumesces before the blowpipe, and then melts into a transparent globule. 2. The natural salt, the natural-historical properties of which are as yet unknown, occurs in different districts of Persia and Thibet, where it is found on the surface of the soil, in the vicinity, and sometimes at the bottom, of several lakes, and in a state of solution in the waters of mineral wells. It is said also to have been met with in Ceylon, and in considerable quantity in Potosi. 3. The natural salt is employed in manufacturing the artificial one by the addition of a greater quantity of soda. The artificial salt is made use of as a flux, in the produc- tion of imitation gems, and in the process of soldering. GENUS X. BRITHYNE*-SALT. 1. PRISMATIC BRITHYNE-SALT. Glauberite. JAM. Syst. II. p. 613. Prismatic Glauberite. Man. p. 19. Glauberite. PHILL. 198. Glauberit. HAUSM. III. S. 839. Brongniartin. LEONH. S. 618, Glaube'rite. HAUY. Tabl. comp. p. 23. Traite', 2de Ed. T. II. p. 215. Fundamental form. Scalene four-sided pyramid. P = { }J£ Jf, }, 128° 0' ; 90° 0'. Inclina- tion = £&° 49' in the plane of the long diagonal. Vol. I. Fig. 41. HAUY. a : b : c : d = 2-3717 : 4 : 3-0984 : 1. * From fyi§i>; dense (heavy). ORDEB IV. PRISMATIC BRITHYNE-SALT. 55 Simple forms. P-co(P); ± ? {{} = _ p (M _ g()0 1102° 21'' -3- W> hoo(Jf;- 6' ; — |^(0 = 74° 29' ; £ r + OD (*). Char, of Comb. Hemi-prismatic. Inclination of P— oo to P r + OD = 112° 49' ; to £ = conchoidal. Surface; P — oo and still more so, — streaked parallel to their common edges of com- bination. P -f oo partly uneven, but smooth and shining. Lustre vitreous. Colour yellowish or greyish- vrhite. Streak white. Semi-transparent ... translucent. Brittle. Hardness = 2-5 ... 3-0. Sp. Gr. 56 PHYSIOGRAPHY. CLASS i. = 2-807, of a solitary crystal. Taste saline and astringent, feeble. OBSERVATIONS. 1. According to measurements with the reflective gonio- meter by Mr PHILLIPS, the angle of P given above as = 120° 12' is equal to 116° 20', that of P + » equal to 83° 20', and the incidence of P — 05 upon P + co = 104° 15'. 2. The prismatic Brithyne-salt consists, according to BRONGNIART, of Sulphate of Lime 49-0. Sulphate of Soda 51-0. Its chemical composition is expressed by Na S3 + Ca S9, and it consists accordingly of 22-35 Soda, 20-35 Lime, and 57'39 Sulphuric acid ; that is to say, of one atom of anhy- drous sulphate of lime, and one atom of anhydrous sulphate of soda. The forms of both these substances are prismatic, those of the prismatic Brithyne-salt are hemi-prismatic. Hence it is not one of those cases, in which one of the sub- stances contained in the mixture impresses its form upon the whole, as is the case in hemi-prismatic Vitriol-salt, which may contain sulphate of copper without change of form. Also the determined proportions in the constituent parts of the Brithyne-salt agree with this observation. If immersed in water, it loses its transparency, and is partly dissolved. The same happens if exposed to a moist atmo- sphere. Before the blowpipe it decrepitates and melts into a white enamel. 3. It occurs in imbedded crystals in hexahedral Rock- gait, at Villarubia near Ocana in New Castile. Another locality is Aussee in Upper Austria. The combinations described above have been observed in the Spanish variety. CLASS II. HALOIDE. BARYTE. KERATE. MALACHITE. MICA. SPAR. GEM. ORE. METAL. PYRITES. GLANCE. BLENDE. SULPHUR. ORDEE I. HALOIDE. GKNUS I. GYPSUM-HALOIDE. 1. PRISM ATOIDAL GYPSUM-HALOIDE. Axifrangible Gypsum. JAM. Syst. Vol. II. p. 615. Pris- matoidal Gypsum. Man. p. 20. Gypsum. Sulphate of Lime. PHJLL. p. 174. Gips. Fraueneis. WEHX. Hoffm. H. B. III. 1. S. 105. 116. Gyps. Stink- gyps. HAUSM. III. S. 887. 893. Wasserhaltiger schwefelsaurer Kalk. LEONH. S. 549. Chaux sulfa- te'e. HAIJY. Traite', T. II. p. 266. Tabl. comp. p. 9. Traite', 2de Ed. T. I. p. 527.. WEISS. Schriften der Acad. der Wiss. zu Berlin fur 1820, u. 21. SORET. Ann. des Min. II. 435. III. 487- Fundamental form. Scalene four-sided pyramid. P = | ^ ^ | , 123° 36', 70° 23r. Inclination = 9° II7 in the plane of the short diagonal. + Pr runk.) __ f53° 8'1 y , j- Fi 41 - -3- 1 T J - (66052'r HAUY. a : b : c : d : = 6-2 : 10'8 : 15-4 : 1. P 1n\ f 143° 52') p , Simple forms, ± — \ ^ : = \ 138o 54/ f , i? 58 PHYSIOGRAPHY. CLASS II. (/) = 110° 37' ; — (-— ^ (x, Soret) — 106° 16' ; (Pr + x)3 (h, Sor.) = 71° 41'; — (*, Sor.) = 83° 18'; (P 4- x)5 (7j, Sor.) =r 51° 20' ; f r (w, A'or.) = ISO0 8' ; Pr + x (P) ; = 8So a, . pr + Char, of Comb. Hemi-prismatic. Inclination of P — oc to Pr + oo = 99° 11'. p Combinations. 1. _ P _j_ x. Pr + cx>. Fig. 57. Shotoverhill near Oxford. P P 2. — — - . P + x. f r + x. Kommothau, Bohemia. 3. L. — l2?-ZL?.P+ x.Pr+ x. Shotoverhill. p 4 -pr2 _ Q 4. £_. — l":±i. P + QD. (Pr + QD)». 2 <* Pr + x. Fig. 58. Bex, Switzerland. Cleavage. Pr -}- x, highly perfect and easily obtain- ed ; — —•> and Pr -f x imperfect, the latter of these being of a conchoidal appearance, while the former is difficultly obtained, on account of the flexibility of the mineral in that direction, p and often of a fibrous aspect. Traces of — — . a Fracture scarcely perceptible. Surface. P + CD and Pr -f- x streaked parallel to ORDER I. 1>RISMATOIDAL (iY PSUM-HALOIDE. 59 their common intersections. The faces of 4 pj. g P — I and + — commonly rounded, 2 2 * which gives rise to the well known lenticular shapes, if in combinations like 3, the faces of P + x and Pr + oo disappear. Lustre vitreous. Pr + oo possesses a pearly lustre, more or less distinct, both upon faces of cleavage and faces of crystallisation. Colour, generally white, sometimes inclining and passing into smalt-blue, flesh-red, ochre-yellow, honey-yellow, and several shades of grey. Im- pure varieties assume dark-grey, brick-red and brownish-red tinges. Streak white. Transpa- rent ... translucent. Sectile. Thin laminae are flexible in the direction of those edges which arise from the intersection of Pr + oo, with - *^p?, and — *£_. Hardness = 1*5 ... 2-0. The lowest degrees upon Pr -j- x, the highest degrees in the direction of p — GO, in which the crystals very often are rounded. Sp. Gr. = 2-310, a perfectly trans- parent crystal from Oxford. Compound Varieties. Twin-crystals. 1. Axis of revolution perpendicular, face of composition pa- rallel to Pr -f oo. (Hence forms like the Chaux sul- Jutee prominule of HAUY). 2. Axis of revolution perpendicular to Pr -f oo ; face of composition pa- rallel to Pr -h x. 3. Axis of revolution per- CO PHYS10GJIAPHY. CLASS II. Pr pendicular, face of composition parallel to -f _. " (According to this law are formed the arrow-shap- ed twins, consisting of lenticular crystals). Globu- lar masses, generally formed of discernible indivi- duals. Dentiform. Massive : composition granular, passing into impalpable, sometimes scaly ; also co- lumnar, often as thin as hair, long and generally straight and parallel. Sometimes without cohesion of the single particles in the state of powder. OBSERVATIONS. 1. The forms, as given above, depend upon the deter- minations of HAUY, and the subsequent labours of Mr SORET on the crystallisations of this substance, attention being given to the inclination of the axis. The connexion among them appears more simple and conformable, to nature, than in any of the representations that have hitherto been given of the same subject ; yet the more accurate deter- minations of the angles by means* of the reflective gonio- meter have not yet been introduced ; and according to these, it will be necessary in future to correct the angles. According to PHILLIPS, the angle of P + os is = 111° 20'. Within the species of prismatic Gypsum-haloide, two species, Fraueneis or Sclenite, and Gypsum, used to be for- merly distinguished, without, however, allowing deter- mined limits to be indicated between them, and which on that account, though not from reasons of Natural History, have been again united by most mineralogists. Such va- rieties as are pure, transparent, and, in short, most perfect- ly formed, were comprehended within the first, less per- fectly formed varieties within the second of the above- mentioned species. The latter, or Gypsum, was divided into several sub-species, comprehending almost exclusively compound varieties pretty easily distinguishable from each ORDER I. PBISMATOIDAL GYPSUM-HALOIDE. 61 other, as their division depends upon the size of the grain or composition in general Thus foliated Gypsum consists of discernible granular particles, compact Gypsum of impal- pable particles of composition ; scaly foliated Gypsum con- sists of minute scaly particles, earthy Gypsum of a mealy powder. Very thin columnar composition produces fibrous Gypsum. 2. Prismatoidal Gypsum-haloide consists of Lime 33-0. Sulphuric Acid 44-8. Water 21-0. BUCHOLZ. It is represented by Ca S2 + 4 Aq, which corresponds to 32-91 of Lime, 46-31 Sulphuric acid, and 2078 Water. The analysis refers to a variety of Fraueneis ; but most of the rest very nearly agree with it. Before the blowpipe it exfoliates, and melts, though with difficulty, into a white enamel, which after a short time falls into powder. In a lower degree of heat it loses its water and becomes friable, so as to be easily reduced to an impalpable powder. If mixed with water, this powder becomes warm, and soon hardens into a solid mass. 3. Compound varieties of this species form beds in se- condary mountains, more sparingly in the older classes of rocks ; they generally possess a considerable thickness, though they are of a very limited extent in length and breadth. It is less frequently met with in veins and beds, ac- companying minerals of the orders Glance, Blende, Pyrites, sometimes hexahedral Gold, &c. In its more peculiar re- positories, it is accompanied by compound varieties of rhombohedral Lime-haloide, hexahedral Rock-salt, by dif- ferent kinds of sandstone and clay in alternating layers, in the latter of which it also occurs in imbedded masses or crys- talline groupes. Very often brine springs issue from the rocks in its vicinity. In some places it is associated with prismatic Sulphur and prismatoidal Hal-baryte. Simple varieties are chiefly found in salt-works, also in abandoned mines and old heaps, where they must be considered as products of more recent formation. Of the organic re- £ PHYSIOGRAPHY. CLASS II, mains found in gypsum, those of extinct species of terres- trial quadrupeds in the Montmartre near Paris, are the most remarkable. 4. The prismatoidal Gypsum-haloide occurs in a great many countries. It is found in various modifications, both crystallised and massive, in different parts of Germany, particularly in Mansfeld, Thuringia, Bavaria, Franconia, Suabia, in the neighbourhood of Liineburg, in Switzerland, in the Tyrol, in Stiria and Austria ; also in Poland, Hun- gary, and Transylvania ; in England, France, Spain, &c. Beautiful crystals are met with near Oxford, at Bex in Switzerland, at Hall in the Tyrol, in several places in Upper Austria, Stiria, Salzburg, and Sicily, &c. ; large lenticular crystals, generally twins, and the scaly varieties, are known from Montmartre near Paris ; the earthy ones from Saxony and Thuringia. 5. This species is variously employed in manufacturing artificial marble, stucco work, mortar, &c. ; also for making casts of statues, medals, &c. It is added to the mass of certain kinds of porcelain and glass. In sculpture it is used under the name of Alabaster. It is also used in agri- culture, for improving the soil, both calcined and in its natural state ; it forms the paste of coloured drawing pen- cils ; it is employed in polishing, &c. 2. PRISMATIC GYPSUM-HALOIDE. Prismatic Gypsum, or Anhydrite. JAM. Syst. Vol. II. p. 605. Man. p. 25. Anhydrous Gypsum. Anhydrite. PHILL. 172. Muriazit. WERN. Hoffm. H. B. III. 1. S. 123. Karstenit. HAUSM. III. S. 881. Wasser- freier schwefelsaurer Kalk. LEONH. S. 546. Chaux sul- fatee anhydre. HAUY. Traite', T. IV. p. 348. Chaux anhydro-sulfatee. Tabl. comp. p. 10. Traite', 2de Ed. T. I. p. 562. BOURNON on Bardiglione. Trans, of the Geol. Soc. Vol. I. p. 355. Fundamental form. Scalene four-sided pyramid. P = 121° 32', 108° 35', 99° T. Vol. I. Fig. 9. HAUY. ORDER I. PRISMATIC GY1'SUM-I1 ALO1DE. a:b:c = l : Jl^G-l? : %/ 1-2353. Simple forms. P — oo (P) ; P («) ; (Pr)3 (n) ; (P)3(/); P+oo(r) = 10G°IO'; Pr.-f oo (T); Pr -f- co (I/). Char, of Comb. Prismatic. Combinations. 1. P — cc. Pr -f oo. Pr -j- oo. Aus- see, Stiria. 2. P — oo. P + oo. Pr + oo. Pr 4- oo. Hall, Tyrol. HAUV. 3. P— oo. P.(Pr)*. (P)*. Pr+Qo. Pr + oo. Fig. 26. Aussee, Stiria. Cleavage. Pr 4- GO and Pr + oo highly perfect; P — x less distinct, yet easily obtained. Fis- sures in the interior partly iridescent parallel to Pr = 106° 3'. Fracture imperfect conchoidal, uneven. Surface, Pr -f x and Pr -f- oo smooth ; P — x rough. Lustre vitreous, inclining a little to pearly upon the most distinct faces of cleavage. Colour generally white ; commonly it inclines to flesh- red, violet- and smalt-blue or ash-grey. Streak greyish-white. Transparent, not perfectly, pass- ing into translucent. Brittle. Hardness = 3-0. . .3-5. Sp. Gr. = 2-899 a greyish-white cleavable variety from Hall in the Tyrol. Compound Varieties. Contorted : composition columnar in thin fibres, parallel, and variously bent. Massive : composition granular, of differ- ent sizes, sometimes impalpable, and then the frac- 6*4? PHYSIOGRAPHY. CLASS n. ture is splintery : in other massive varieties the composition is columnar, commonly thin and pa- rallel. Faces of composition rough. OBSERVATIONS. 1. The species Muriacite of the Wernerian System is sub- divided into five different kinds, pretty easily distin- guishable, but not provided with the best nomenclature. Thus the Cubic Muriactte, also called Cube-spar, compre- hends simple varieties, and easily cleavable compound ones, in which the individuals possess a considerable size. The name of Anhydrite has been given to varieties of a smaller granular composition, and that of Gelcrosstcin or pierre de trippes to the contorted compositions consisting of thin co- lumnar individuals. Compact and fibrous Muriacite were the denominations of compound varieties of very small indi- viduals, the one granular and impalpable, the other co- lumnar. The Vulpinite of Italy, so named from its locali- ty, is composed of granular individuals, a little longer in one direction, of a greyish-white or grey colour, and very much resembling a coarse grained primitive marble. 2. A cleavable variety from Hall in theTyrol has been found to consist of Sulphuric Acid 55*00. Lime 41 '75. Muriate of Soda 1-00. KLAPROTH. Except the muriate of soda, the rest of the varieties have presented nearly the same proportions. The Vulpinite contains a little silica, probably from imbedded crystals of rhombohedral Quartz. The chemical formula for the pure mixture of this mineral is Ca S*2, which gives 41-53 of lime, and 58-47 of sulphuric acid. It does not exfoliate be- fore the blowpipe, but is covered with a white friable enamel. By a peculiar process, the prismatic Gypsum-haloide at- tracts water, loses its transparency, a portion both of its hardness and specific gravity, and approaches in some of ORDER I. PRISMATIC GYPSUM-HALOIDE. 65 these properties to the preceding species, which generally occurs along with it, particularly in small crystals lining the fissures which traverse the mass in all directions. Cleav- age yet enables us to distinguish this decomposed substance, which has been called Chaux sulfatie epigene by HAUY, from the real and determinable varieties of prismatoidal Gyp- sum-haloide. The change is here exactly the reverse of what happens in the decomposition of hemi-prismatic Na- tron-salt, and of prismatic Glauber-salt, &c., which lose their water, instead of attracting a portion of it, like the prismatic Gypsum-haloide. 3. The repositories of the preceding species are in general at the same time those of the present one, by which it is commonly accompanied : yet it does not form beds by it- self. It is also found along with metallic minerals, as at Bleiberg in Carinthia, with hexahedral Lead-glance, and occurs in globular masses of various sizes in the beds ojf clay, which accompany prismatoidal Gypsum-haloide and hexahedral Rock-salt. 4. Splendid geodes of large and well defined crystals (Fig. 26.) of this species have been found at Aussee in Stiria, other crystallised varieties at Hall in the Tyrol, at Hallein in Salzburg, in Switzerland, &c. ; accompanied by large grained cleavable masses. The blue Anhydrite is found at Sulz on the Neckar, and at Bleiberg in Carin- thia. Columnar varieties occur at Ischel and Berchtesga- den ; compact ones, besides these localities, also in the Hartz, in Mansfeld, &c. ; the contorted varieties are found at Wieliczka and Bochnia in Poland. The decom- posed prismatic Gypsum-haloide occurs in considerable masses at Aussee in Stiria, at Bex in Switzerland, and other places. 5. The blue varieties, in which the granular particles of composition cohere more firmly than in others, are cut and polished for various ornamental purposes, as also in Italy the Vulpinite, which has been called Marino bar, digtto di Bergamo. VOL. II. E C6 PHYSIOGRAPHY. CLASS n. GENUS II. CRYONE-HALOIDE. 1. PRISMATIC CRYONE-HALOIDE. Prismatic Cryolite. JAM. Syst. Vol. II. p. 601. Man. p. 28. Cryolite. PHILL. p. 197- Kryolith. WERN. Hoffm. H. B. III. 1. S. 204. Kryolith. HAUSM. III. S. 846. Kryolith. LEONH. S. 624. Alumine fluate'e alcaline. HAUY. Traite', T. II. p. 398. Tabl. comp. p. 23. Traite', 2de Ed. T. II. p. 157. Fundamental form. Scalene four- sided pyramid of unknown dimensions. Vol. I. Fig. 9. Simple forms and combinations unknown. Cleavage. P — oo perfect. Pr + oo and Pr + oo less perfect or coherent. Traces of P. Fracture imperfect conchoidal, uneven. Lustre vitreous, a little inclining to pearly upon the faces of P — oo. Colour white, sometimes verging upon red or yellowish-brown. Streak white. Semi-transparent ... translucent. On account of its low refractive power, it appears more transparent when immersed in water. Brittle. Hardness = 2-5... 30. Sp. Gr. = 2-963 of a white variety. Compound Varieties. Massive: composition granular, the individuals being of considerable size. OBSERVATIONS. 1. The prismatic Cryone-haloide consists of Alumine 21-0 24-0. Soda 32-0 36-0. Fluoric Acid and Water 47-0 40-0. KLAPROTH. VAUQUELIN. It is considered by BERZELIUS to be the compounds Na F + Al2 F3. It is very easily fusible, even at the flame of ORDER I. RIIOMBOHEDRAL AL0M-HALOIDE. 67 a candle. Before the blowpipe it is first perfectly liquefied, but soon becomes hard again, and assumes at last a slaggy appearance. It is insoluble in water, though it appears in it of a higher degree of transparency, and, according to Mr ALLAN, more easily admits of cleavage, after having been kept in it for some time. 2. It occurs in Arksut-fiord, West Greenland, in two small layers in gneiss, one of which contains only the white varieties, whereas the other contains the coloured ones accompanied by hexahedral Lead-glance, several spe- cies of Pyrites, rhombohedral Quartz, and imbedded crys- tals of brachytypous Parachrose-baryte, and prismatic Feld-spar. GFKCS III. ALUiM-HALOIDE. 1. RHOMBOHEDRAL ALUM-HALOIDE. Rhomboidal Alumstone. JAM. Syst. Vol. II. p. 599. Man. p. 29. Alum-stone. PHILL. p. 196. Alaun- stein. WERN. Hoffm. H. B. II. 2. S. 78. Alaunstein. HAUSM. II. S. 465. Alaunstein. LEONH. S. 623. Lave alte'ree alunifere. HACY. Traite, T. IV. p. 504. Alumine sous-sulfatee alcaline. Traite', 2de Ed. T. II. p. 128. COHDIER. Ann. de Chim. Vol. IX. p. 71- Fundamental form. Rhombohedron. R = 92° 5CK. Vol. I. Fig. 7. PHILLIPS. a = V 3-892. Simple forms. R — oo (6) ; R (R). Char, of Comb. Rhombohedral. Combination. 1. R — oo. R. Fig. 111. Cleavage. R — oo rather perfect. Traces of R. Surface, smooth and even. The faces of R sometimes streaked parallel to their edges of com- bination with R — GD. Lustre vitreous, inclining to pearly upon the more 69 PHYSIOGRAPHY. CLASS n, distinct faces of cleavage. Colour white, some- times reddish or greyish. Streak white. Trans- parent ... translucent. Brittle. Hardness = 5-0. Sp. Gr. = 2-694 of a crystallised variety from Tolfa. Compound Varieties. Massive : composition small granular, often impalpable; fracture uneven, flat conchoidal, splintery, sometimes earthy. In the interior of the massive varieties, there are cavities lined with crystals. OBSERVATIONS. 1. This species consists, according to CORDIER, who analysed a variety from Tolfa, of Sulphuric Acid 35-495. Alumina 39-654. Potash 10-021. Water and loss 14-350 ; with a trace of oxide of iron. Upon charcoal before the blowpipe it does not melt by itself, nor with soda, but is fusible into a colourless globule with borax. Reduced to powder, it is soluble in sulphuric acid. 2. Rhombohedral Alum-haloide is found at Tolfa near Civita Vecchia, in the vicinity of Rome ; also in Tuscany, in the kingdom of Naples, and in the county of Beregh in Hungary, also in the neighbourhood of several active vol- canoes. It seems to form beds in these places. According to PRZYSTANOWSKY, the beds of rhombohedral Alum-ha- loide in Italy occur in Quartz, which is here and there mixed with clay. According to others it is found in veins and geodes of a particular kind of rock, which has been called the Alum-rock, and which probably consists of compact varieties of the same species. 3. It is used in the manufacture of alum ; and the su« ORDER I. OCTAHEDRAL FLUOR-HALOIDE. 69 perior quality of that produced at Tolfa is ascribed to the employment of this mineral. GENUS IV. FLUOR-HALOIDE. 1. OCTAHEDRAL FLUOR-HALOIDE. Octahedral Fluor. JAM. Syst. Vol. II. p. 587- Man. p. 29. Fluor. Fluate of Lime. PHILL. p. 168. Fluss. WERN. Hoffm. H. B. III. 1. S. 94. Fluss. HAUSM. III. S. 876. FlusssaurerKalk.LEONH.S.561. Chaux fluatt'e. HAUY. Traite',T. II. p. 247- Tabl. comp. p. 8. Traite', 2de Ed. T. I. p. 505. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (z), Alstonmoor; O (P) Vol. I. Fig. 2., Moldawa, Bannat; D (*), Vol.1. Fig. 31., Ehrenfriedersdorf, Saxony. As (#), Vol. I. Fig. 32. ; As (#), Cornwall ; B, Vol.1. Fig. 33. Ci, Vol. I. Fig. 34-. ; Ca (u), Zinnwald, Saxony ; Ts (w) Vol. I. Fig. 35. Char. of. Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4. St. Gallen, Stiria. 2. H. D. Fig. 151. Falkenstein, Tyrol. 3. H. As. Fig. 148. St Agnes, Cornwall. 4. H. Cs. Fig, 149. Zinnwald, Saxony. 5. H. Ts. Matlock, Derbyshire. 6. O. As. Altenberg, Saxony. 7. H. O. D. Schwarzenberg, Saxony. 8. H. D. Ce. Falkenstein, Tyrol. Cleavage. Octahedron, perfect and easily obtain- ed. Dodecahedron and hexahedron sometimes distinct in the green varieties from Alstonmoor, 70 PHYSIOGRAPHY. CLASS n. the first also in a dark violet blue variety from St. Gallen in Stiria, the second in the yellow hexa- hedral varieties from Saxony. Fracture con- choidal, more or less perfect. Surface. The hexahedron generally smooth. Oc- tahedron often rough and drusy. Dodecahedron various, being sometimes smooth, at other times rough or drusy. Hexahedral trigonal-icositetra- hedrons commonly streaked parallel to their edges of combination with the dodecahedron. Some- times the faces of the hexahedron and the tetra- conta-octahedrons are curved. Lustre vitreous. Colour white, though not very common, and seldom pure. Generally wine -yellow or violet-blue. Among its brightest colours are emerald- and pistachio-green, sky-blue, rose-red, and crimson- red. Very dark blue colours, bordering upon black, probably owing to foreign admixtures. Frequently different shades of colours are dis- posed in coats parallel to the faces of the hexa- hedron, or symmetrically distributed along the edges or solid angles of crystals. Streak white. It is sometimes slightly tinged, if the colours be very deep. Translucent ... transparent. Sometimes different colours appear by reflected and by transmitted light. Brittle. Hardness = 4-0. Sp. Gr. = 3-140, violet-blue crystals from St. Gallen in Stiria, ORDER I. OCTAHEDUAL FLUOR-HALOIDE. 71 Compound Varieties. Twin-crystals. Axis of revolution perpendicular, face of composition pa- rallel to one of the faces of the octahedron ; the in- dividuals, having one of their axes parallel, are continued beyond the face of composition, and par- ticles of the one are observed formed upon the faces of the other. Fig. 128. Implanted globular shapes, rare : surface drusy, composition columnar. Massive : composition granular, the individuals being of various sizes ; if the composition be impalpable, the fracture becomes flat conch oidal and splintery, the surface of fracture being scarcely glimmer- ing. Massive varieties are also sometimes com- pound of columnar particles, generally of consider- able size, seldom thin or diverging, but very often forming a second curved lamellar composition. The faces of composition are sometimes irregularly streaked, more generally uneven and rough. OBSERVATIONS. 1. Fluor has been divided into foliated and. compact Fluor, of which the first is more generally called Fluor-spar. This division comprehends the simple varieties, and such compound ones as consist of individuals, whose cleavage can still be ascertained. The other includes those in which the individuals are too small to allow cleavage to be observ- ed. This division is not erroneous, but it is useless. A third sub-species has been added to the former two, which comprehends the earthy Fluor, or the friable varieties of the species, in which the individuals have lost their con- nexion, probably by decomposition. 2. Octahedral Fluor-haloide consists of Lime 67-75* Fluoric Acid 32-25. KLAPKOTH. PHY3IOGBAPHY. CLASS u. According to BERZELIUS it is expressed by Ca F, and composed of 72-14 of Lime, and 27'86 of Fluoric acid. Before the blowpipe it decrepitates, and becomes phosphorescent, but loses its colour, and melts at last into a rather opake globule. It phosphoresces likewise, if thrown upon ignited charcoal or heated iron. Several varieties, which exhibit this phenomenon in particularly bright green colours, have been called Chlorophane or Pyro-smaragdus. If ex- posed to a too high degree of temperature, they lose the property of again shewing this phenomenon. Sulphuric acid decomposes the powder of the mineral ; fluoric acid is disengaged in a gaseous state, and corrodes glass. Several varieties, particularly the sky-blue ones, lose their colour, on being exposed to light. 3. This species does not enter as a regular constituent into the composition of rocks. It is not very frequently found in beds ; this, however, seems to be the case at Al- stonmoor and Castleton ; some varieties occur in beds of octahedral Iron-ore, pyramidal Copper-pyrites, &c. More generally it is found in veins, with various minerals, in an- cient and more modern rocks. Very seldom it is associated with petrifactions, as the blue varieties of Derbyshire with entrochites. 4. Octahedral Fluor-haloide is common in some coun- tries, while in others it is very rare. Among the first we notice Saxony, some districts of the Hartz, and England, among the last Scotland, Hungary, Transylvania, &c. Most beautiful and interesting crystallized varieties are found at Beeralston in Devonshire, at St Agnes and other places in Cornwall, and at Zinnwald in Bohemia ; also some rare colours, as for instance the sky-blue ones. Large crystals, generally twins of the hexahedron, of beautiful green and blue colours, occur at Alston in Cumberland, which frequently contain water. Beautiful dark blue per- fect crystals, of the form Fig. 148., have been found, in small geodes, along with rhombohedral Quartz, near Gou- rock in Renfrewshire. They here occur in porphy- ORDER I. RHOMBOHEDRAL FLUOH-HALOIDE. 73 ritic greenstone. Well defined octahedrons of an apple- green colour at Moldawa, in the Sannat of Temeswar. Hose-red octahedrons are met with near Chamouni in Savoy, associated with tabular crystals of rhombohe- dral Lime-haloide ; emerald-green octahedrons have been brought from America. The Saxon varieties are gene- rally of a hexahedral form, and violet-blue or wine-yel- low colours ; yet there occur some of other forms and co- lours, both in Saxony and the adjacent districts of Bohemia. The compound uncleavable varieties (compact fluor) are chiefly known from Strassberg and Stollberg in the Hartz, Cornwall, and Sweden. The friable ones (earthy fluor) are found in Saxony, England, and Norway. Several parts of Germany, France, Siberia, America, &c. produce likewise varieties of this species. 5. Octahedral Fluor-haloide, particularly those varieties which consist of columnar particles of composition, are cut and polished for various ornamental purposes. In Derby- shire they are turned into vases, for which, however, they require first to be prepared by certain processes, which in- crease their tenacity. In former times, those of fine co- lours used to be cut and worn as gems, and were designated by the same names. A more important employment is that of fluxing several ores, from which the name of Fluor has been derived. The fluoric acid, disengaged from it by means of sulphuric acid, has been used for corroding and etching upon glass. 2. RHOMBOHEDRAL FLUOK-HALOIDE. Rhombohedral Apatite. JAM. Syst. Vol. II. p. 575. Man. p. 32. Apatite. Phosphate of Lime. PHILL. p. 167- Apatit. Spargelstein. Phosphorit. WERN. Horfm. H.B. III. 1. S. 84. 89. 92. Apatit. Phosphorit. HAUSM. III. S. 869. 872. Phosphorsaurer Kalk. LEONH. S. 557. Chaux phosphate'e. HAUY, Traite', T. II. p. 234. Tabl. comp. p. 7- Traite', 2de Ed. T. I. p. 487- HAIDIXGEB. Edin. Phil. Jouru. No. XIX. p. 140. 74 PHYSIOGEAFHY. CLASS 11. Fundamental form. Rhombohedron. R = 88° 41'. Vol. I. Fig. 7. R. G. a = J 4-8245. Simple forms. R — oo (P) ; R — 1 (a) ; 11 (s) ; R + 1 ; R + oo (e) ; P — 1 (r) = 157° 33', 45° 49' ; P O) = 142° 20', 80° 25' ; P + 1 (2) = 129° 1', 118° 48' ; P + oo (3/) ; (P)* (w) ; 141° 47' 12"; (P + . 2(R — 1). P. 2(R). P+l. R + ao r 2 r 2 Fig. 148. St. Gotthard. 6. R — oo. P — 1. 2 (R — 1). P. 2 (R). P + l. . . R + oo. r 2 r 2 P + oo. Fig. 149. St. Gotthard. Cleavage. R — oo and P + oo, not perfect, the lat- ORDEil I. KHOMBOHED11AL FLUOR HALOIDE. 75 ter generally more easily obtained. The aspa- ragus-green varieties from Salzburg, imbedded in talc, shew very smooth faces of cleavage, par- ticularly in the direction of P + &> which, how- ever, are interrupted by conchoidal fracture. Fracture conchoidal, more or less perfect, uneven. Surface, the dirhombohedrons and pyramids ge- nerally very smooth. P — 1, sometimes rough, though even, sometimes horizontally streaked. R — oo frequently a little curved or uneven. The vertical prisms often deeply striated in a longi- tudinal direction. Sometimes all the edges are rounded. Lustre vitreous, inclining to resinous. Colour white, though not general. Frequently violet- blue, mountain-green, or asparagus-green ; also yellow, grey, red, and brown colours, none of them bright. Transparent, but generally trans- lucent. A blueish opalescence appears upon the faces parallel to the principal axis in some crys- tals, particularly the white varieties. Brittle. Hardness = 5-0. Sp. Gr. = 3-225, asparagus-green crystals from Spain ; = 3-180, from Salzburg. Compound Varieties. Implanted globular and re- niform shapes : composition imperfect columnar, faces of composition rough. Massive : compo- sition granular, individuals of different size, not impalpable, faces of composition uneven or rough. L) PHYSIOGRAPHY. CLASS II. OBSERVATIONS. 1. The most remarkable feature in the series of crystalli- sation of rhombohedral Fluor-haloide is the mode in which the scalene six-sided pyramids enter into combinations with other forms. It is the mode called hemi-rhombohe- dral parallel with faces (Vol. I. §. 147-), and is not as yet known with the same peculiarities in any other species. If sufficiently enlarged, the faces marked u^ u &c., and &, & &c., Fig. 148. and 149. will produce forms which by themselves appear as isosceles six-sided pyramids if we give no atten- tion to their connexion with other simple forms of the species. In LEONHARD'S Mineralogy, mention is made of this peculiarity, but it is -said to be unsyrnmetrical, and like the Quartz plagiedrc of HAUY, from which, however, it is distinguished by having the oblique faces disposed on one end to the right, on the other to the left of the faces of 2 (R), while in Quartz they are disposed on both ends of the crystals, equally, either to the right or to the left of the same faces. The twelve-sided prisms (P + co)5 and (P + os)3, though derived according to different numbers of deriva- tion, yet possess the same transverse sections, with that difference only that the obtuse edges of the one have the situation of the acute edges of the other. These prisms also produce hemi-dirhombohedral combinations with other forms, so that if we find the alternating faces of (P + cc)3 contiguous to the left side of the faces of 2 (R), the right ones of (P + co)3 will appear. The product of a combina- tion of R + cc, P + co, I 2_±f^ and _! 2_±^I3 is r 2 12 limited parallel to the axis by four times six faces of the same kind, including angles with each other of alternately 160° 53' 38" and 169° 6' 24", so that, proceeding from right to left, the edge of combination between - _.fii_ and /p , ^Yj 11 + co is equal to that between ^ — I and P + co, 2 and so all round. ORDER I. RHOMBOHEDRAL FLUOR- II ALOIDE. 77 As has been shewn in Vol. I. §. 115., this equality of the angle is a general relation in the rhombohedral system, where, from the formula m = 3m/+1 it appears that m = 3 3(tn'--i) gives m' = §, that m = 2 gives m' = £, &c. It is deserv- ing of notice, that if T i , the first variety of tetraconta-oc- tahedrons (Vol. I. §. 77-)> be placed in an upright position, so as to have one of the rhombohedral axes vertical, and the hexahedron be supposed = R, as the fundamental form of the series ; the vertical faces will be expressed by the sign (P + co)5. The inclined faces would be, upon the same supposition, P — 1. (P — I)2. (P — I)5. 2. The varieties of the present species, by no means less distinct than those of the preceding one, decidedly sepa- rate from others and connected among themselves, have been considered by some mineralogists as forming two or even three different species, and farther subdivided into several sub-species or kinds. The distinctive marks be- tween them, however, are so slight, that they cannot be indicated with precision, nor usefully employed in an actual distinction. It would be superfluous, therefore, to attempt their explanation. The varieties of Apatite, Asparagus-stone, and Phosphorite, are so intimately con- nected, that they pass insensibly into each other ; and thus demonstrate that in fact they form but one and the same species, which is an immediate consequence of the transi- tions, and in the present species was first ascertained by the Abbe HAUY. 3. Rhombohedral Fluor-haloide consists of Lime 55-0. Phosphoric Acid 45-0. KLAPROTH. It is Ca3 P2, according to which formula the proportion of lime to that of phosphoric acid will be as 54-48 : 45-52. It is slowly soluble in nitric acid, and without effervescence. Some varieties are phosphorescent upon ignited charcoal and before the blowpipe, others even when rubbed with hard bodies. In a very strong heat of the blowpipe, the 78 PHYSIOGRAPHY. CLASS II. edges and solid angles are rounded off, but it does not melt without addition. With salt of phosphorus it forms a clear globule. A phosphate of lime has been artificial!}7 obtained in lamellar masses of a greyish colour, by the younger SAUSSURE, upon exposing a mixture of phosphoric acid and sulphate of lime to a high temperature. These lamel- lar masses shewed by heat opposite kinds of electricity on opposite ends, a property which HAUY in vain tried to dis- cover in the natural crystals of rhomb ohedral Fluor-haloide. 4. There are examples, though few, of this species en- tering as an occasional admixture into the composition of rocks. Thus the granite of the neighbourhood of Rio Ja- neiro, and the green prismatic Talc-mica, called common Talc of Salzburg, contain varieties of it. More frequently it appears in beds and veins consisting chiefly of ores of iron and tin, particularly in the latter, associated with pyramidal Tin-ore, prismatic Scheelium-ore, prismatic Topaz, several species of Pyrites and Haloides, &c. In another kind of veins, consisting of crystallised varieties of those species of which the rocks themselves are composed, it is accompanied by rhombohedral Quartz, and several species of the genera Feld-spar and Talc-mica. The crys- tallised varieties from Spain, called Asparagus-stone, occur along with rhombohedral Iron-ore and compact rhombohe- dral Lime-haloide ; the compound varieties, or Phosphorite, of the same country, form particular beds. 5. Ehrenfi iedersdorf in Saxony, Schlackenwald in Bo- hemia, the Greiner mountain in Salzburg, Cabo de Gata in Spain, Arendal in Norway, Devonshire and Cornwall in England, afford some of the most generally known locali- ties of fine varieties of rhombohedral Fluor-haloide. Very beautiful crystals of this substance have lately been disco- vered at Carrock in Cumberland, associated with the dif- ferent species, which usually occur in veins and beds of Tin-ore. From St Gothard in Switzerland, and Hei- ligenbluter Tauern in Salzburg, remarkable white, transpa- rent crystals have been brought. Other varieties occur in ORDER I. 1'RISMATIC LIME-HALOIDE. 79 France, Italy, America, &c. ; the Phosphorite is known from Estremadura in Spain, and Schlackemvald in Bohemia. GENUS. V. LIME-HALOIDE. 1. PRISMATIC LIME-HALOIDE. Prismatic Limestone or Arragonite. JAM. Syst. Vol. II. p. 568. Man. p. 34. Arragonite. PHILL. p. 161. Eisenbllithe (Var. of Fasriger Kalksinter). Arragon. WEHX. Hoffm. H. B. III. 1. S. 32. 77- Arragonit. HAUSM. III. S. 972. Arragon. LEONH. S. 584. Arragonite. HALT. Traite', T. IV. p. 337. Tabl. comp. p. 6. Traite', 2de Ed. T. p. 432. Fundamental form. Scalene four-sided pyramid. P = 112° 39', 93° 33', 123° 34'. Vol. I. Fig. 9. AP. a : b : c = 1 : V°'736 : V0-4?6- Simple forms. P — QD (s) ; P — 1 - 129° 11', 116° 1', 85° 58' ; P (r) ; (Pr — I)3 = 92° 56', 129° 40', 108° 5'; (Pr + QD) 3 (M) = 63° 44' ; Pr — 2 (x) = 140° 10' ; Pr — 1 (P) = 108° 8' ; | Pr = 85° 13'; | Pr . + 1 = 49° 24'; I Pr + 1 = 30° 51'; Pr + QD ; £r = 80° 52'; Pr + oo. Char, of Comb. Prismatic. Combinations. 1. P — oo. (Pr + oo)5. Pr + QD. Arragon. 2. Pr — 1. (Pr + oo)5. Pr + oo. Sim. Fig. 9. Leogang, Salzburg. 3. Pr — 2. Pr — 1. f Pr. (Pr+OD)*. Pr + oo. Sim. Fig. 23. Bilin, Bohemia. 4. Pr — 2. Pr — 1. P. (Pr + . MONT. 11. R — 1. (P)3. R -f oo. Derbyshire. 12. (P— 2)3. (P)3. R + oo. Derbyshire. 13. R. (P 4- 1)*. R 4- oo. Alston, Cumber- land. 14. R.(P)3. R4-2. (P)5. R4-oo. Fig. 116. Derbyshire. 15. R _ 1. (p — 2)3. R. I R. R 4- 1. (P)5. R+oo. Vol. I. Fig. 59. Derbyshire. 16. R— -1. (P — 2)3. R. B + l. (P4-1)2- R 4- 2. (P)5. (P + I)3. R 4- 3. Maria- trost, near Gratz, Stiria. Cleavage. R, very easily obtained, even and often highly perfect. Of the forms R — OD, R — 1, R 4- x, P 4- oo and (P)3 faint traces are some- 86 PHYSIOGRAPHY. CLASS II. times observable in a strong light. Curved faces of cleavage commonly originate in composition. Fracture perfect conchoidal, difficult to be ob- tained. Surface generally even, only certain rhombohedrons and pyramids curved. R — oo commonly rough ; II — 1 striated parallel to its own inclined dia- gonals, or to the edges of combination with R ; R -f oo smooth. P and P -f oo streaked paral- lel to their edges of combination with R ; so are likewise the scalene six-sided pyramids belonging to R, and above all (P)5. Lustre vitreous. The lustre of P — oo, particu- larly as a face of composition inclining to pearly. Colour, white, prevalent. Also different shades of grey, red, green, yellow ; all of them pale. Dark brown and black colours, owing to foreign ad- mixtures. Streak greyish- white. Transpa- rent ... translucent. Double refraction very considerable, and easily observed. Brittle. Hardness — 3-0. Sp. Gr. = 2-721, a transparent crystal of the form var. 13. Compound Varieties. Twin-crystals. 1. Axis of revolution perpendicular, face of composition pa- rallel to R — oo, as in Fig. 129. and 135.*, parallel toR — 1, as in Fig. 130. and Fig. 133., parallel to R, as in Fig. 132., or parallel to R + oo, as in Fig. • This figure represents a crystal from Alstonmoor, in the collection of Mr ALLAN, in which the substance of the "individuals is continued beyond the face of composition. H. ORLEK I. UHOMBOHEDEAL LIME-HALOIDE. 87 134. 2. Axis of revolution parallel, face of com- position perpendicular to a terminal edge of R. The regular composition in faces parallel to R — 1, Fig. 130., takes place also in massive varieties, and then more or less thick lamina? of the two in- dividuals alternate with each other, as in Fig. 131. The frequent occurrence of those well known striae upon the faces of cleavage, parallel to the horizon- tal diagonal of the rhombs, depends upon this mode of regular composition. The faces of composi- tion, also those in the direction of R — oo, used formerly to be considered as faces of cleavage. Implanted globules ; stalactitic, botryoidal, fruti- cose shapes: surface uneven, drusy, rough or smooth, composition columnar, more or less distinct, straight, diverging, and of various sizes. Stalactitic and botryoidal varieties are often composed a second time of curved lamellar particles, conformably to the surface of the imitative shape, the faces of composition being uneven and rough, or irregu- larly streaked in a longitudinal direction. Mas- sive: 1. Composition columnar, the individuals being straight, parallel, or diverging, very often of remarkable delicacy. In a second composition, glo- bular masses are produced, consisting of curved la- mellar particles, the faces of composition between the latter often being smooth. These globules are again joined in a third composition, producing gra- nular masses, between which the faces of compo- sition are uneven and rough. 2, Composition gra- 88 PHYSIOGRAPHY. CLASS 11. nular, the individuals being of various sizes, and even impalpable ; faces of composition irregularly streaked, uneven, and rough. The individuals co- here more or less firmly. If the composition be impalpable, fracture becomes splintery, uneven, flat conchoidal, or even ; on a large scale it is some- times slaty. The fracture is earthy in those va- rieties in which the individuals cohere but slightly. 3. Composition lamellar ; the individuals more or less thin, and often bent ; face of composition some- times rough, and possessing a pearly lustre. Glo- bules formed in cavities ; plates, of various kinds of composition. OBSERVATIONS. 1. The species of rhombohedral Lime-haloide is not yet determined with perfect purity and correctness by all mi- neralogists. Even in the system of Abbe H AU Y, it includes, though only as an appendix, substances which do not belong to the species. Pearl-spar, Dolomite, Rhomb-spar, have long ago been separated from the species of rhombohedral Lime-haloide ; and this separation is fully confirmed by the examination of the angles, the degrees of hardness and of specific gravity, which has produced the assumption of the three following species. It cannot yet be maintained, that the number of those species of the present genus, whose forms belong to the rhombohedral system, is thus exhausted ; on the contrary, it is highly probable, that there exist several others, the determination of which has hitherto been im- possible, on account of the want of an exact natural-histo- rical examination. The same takes place in other genera. Differences in the admeasurement of forms, in hardness, specific gravity, &c.f if they be constant and not connected by transitions, necessarily produce different species. Yet OttDEIl I. KHOMBOHEDRAL LIME-HALOIDE. 89 they require most accurate examination ; and this, on the other hand, must serve as a proof that the measures of the angles within a correctly determined natural-historical species, are in fact invariable. The distinction of several species within that of rhombo- hedral Lime-haloide, and the division of them into seve- ral sub-species and kinds, as it used to be in the older Mi- neralogy, depends chiefly upon the mode of composition, and upon admixtures and impurities, with which the indi- viduals have been affected in their formation. Of these, Limestone, if we except Flosferri (p. 83.), represents the greater part of the pure varieties of the species. The simple varieties, and such compound ones in which the in- dividuals are of considerable size, and easily cleavable, have been called Calcareous spar, compound varieties of granular still discernible individuals, are granular Limestone, both comprehended under the head of foliated Limestone. If the granular composition disappear, compact Limestone is formed, under which denomination also the Oolite or Roestone was exhibited. The roundish grains, however, of the latter, consist of columnar individuals, disposed like the radii of a sphere, and frequently shewing distinct traces of cleavage. Common fibrous Limestone is produced by columnar compo- sition in massive varieties, the fibrous Calcslnter by the same, but appearing in various imitative shapes. The lat- ter must be carefully distinguished from similar formations of prismatic Lime-haloide. Pea-stone or Pisolite consists of diverging columnar individuals, collected into curved la- mellar ones, forming globular masses, which are again ag- glutinated by a calcareous cement. Each of the globules generally contains a fragment, sometimes of considerable size, of some heterogeneous matter, as quartz, granite, &c: Compact limestone .passes into Chalk, if the individuals are more loosely connected with each other, so that the whole assumes an earthy appearance ; and Rock-milk or Agaric mineral is formed, if the mass contains so many interstices, that it seems to possess but a small degree of specific gra- 90 PHYSIOGRAPHY. CLASS II. vity. Calcareous tufa, a recent deposit formed on the sur- face of the earth, is often cleavable, and then possesses all the properties of calcareous spar. Slate-spar is produced by a la:nellar composition in massive varieties in the direction of the face of It — os, contained in thin parallel layers. The face of composition, like that of R — co in crystallised individuals, often possesses pearly lustre. The single laminae of slate-spar are cleavable into rhombohedrons, like every other simple variety of the species. There is no transition from slate-spar into Aphrite. Sitnncstonc, Anthracolite^ Marl, Duttenstcin, and bituminous Marlslate, are impure and mixed varieties, partly of calcareous spar, partly of com- pact limestone. The pure varieties of rhombohedral Lime-haloide con- sist, according to the analyses of several of the first che- mists, of Lime 56*0... 57-0. Carbonic Acid 43-0... 44-0. Their chemical formula is Ca C2, which requires 56-39 of lime, and 43-61 of carbonic acid. Very often the varieties contain a small proportion of oxide of iron, silica, magnesia alumina, carbon or bitumen. Rhombohedral Lime-haloide, if pure, is entirely soluble in nitric acid, during which a brisk effervescence takes place. In common fire it is infusible, but loses its carbonic acid, and becomes burnt, or quick lime. 3. Rhombohedral Lime-haloide rarely enters into the composition of rocks. In most cases, the more consider- able masses of it form particular beds in other rocks, or constitute rocks themselves : the latter consist chiefly, though not exclusively, of compact limestone ; the former of granular limestone. The simple varieties occur in drusy cavities, more frequently in veins than in beds, accom- panied with the varieties of different species. There are also compound varieties found in these repositories; co- lumnar compositions have been observed to form veins by themselves, and a great number of varieties are met ORDER I. RHOMBOHEDBAL LIME-IIALOIDE. 91 with in the cavities of several rocks. Slate-spar is gene- rally a product of beds of granular limestone ; calcare- ous tufa and rock-milk, being of a sintery formation, oc- cur upon the surface and in fissures of limestone rocks, and rock-milk in particular is generally a very pure car- bonate of lime. Stalactitic and pisiform varieties are produced by calcareous springs and other waters. The original repository of Anthracolite is unknown, it having as yet been found only in large boulders. A variety of very similar composition, though consisting of smaller individuals, forms a coat round limestone nodules in the lias of Lyme in Dorsetshire ; the axis of the individuals is perpendicular to the surface. The mixed or impure varieties occur in particular strata, between those of com- pound varieties of other species. The rhombohedral Lime- haloide very often occurs in petrifactions, imbedded in compact varieties of the same species. Among these we notice the variety called Lumachella, which is of a dark grey colour, and contains beautifully iridescent shells in a high state of preservation.* " In various petrifactions, the disposition of the crystal- line particles of the present species is very curious. Thus every one of the spines of echini consists of a single indi- vidual, perfectly cleavable, and the axis of which is pa- rallel to the axis of the spine. But, what is still more remarkable, the spines of these animals possess the same property even in recent specimens of the latter, and it ap- pears that the carbonate of lime crystallises as rhombohe- dral Lime-haloide upon the body of those animals. The process of petrifaction seems to require nothing else but the replacement of the animal matter in the pores of these spines by calcareous particles, which will arrange them- selves according to the attraction of the crystalline particles which already exist. The shell of the echini itself consists of several individuals ; and the inside of each of the five am- bulacra is often lined with two rows of crystals, disposed like those individuals, which constitute the shell. The en- crinites are likewise composed of cleavable varieties of calcareous spar. The arrangement of the individuals in a 92 PHYSIOGRAPHY. CLASS n. 4. Rhombohedral Lime-haloide is a species widely dif- fused in nature, and several of its compound varieties have a considerable share in the constitution of mountains in many countries. So they appear in Switzerland, Italy, Carniola, Carinthia, Salzburg, Stiria, Austria, Bavaria, Suabia, &c. The earthy varieties of chalk occur in the low lands, or on the sea-shores of England, France, Den- mark, Poland, &c. Beds of granular limestone occur in gneiss, mica-slate, clay-slate, &c. ; beds of compact lime- stone likewise in the grey wacke formation of the Hartz and other districts, also associated with sandstone, &c. Of crystallised varieties there are some, both simple and com- pound, which are more frequently found in some countries than in others. The most remarkable of them occur in Derbyshire and Cumberland, in the mining districts of Sax- ony and Bohemia, in the Hartz, in Carinthia, Stiria, Hun- gary, France, and other countries. Iceland is the locality of the purest and most transparent varieties, seldom crystallised in the shape of regular six-sided prisms, and which have by preference been called the doubly refracting spar. The crystallised sandstone of Fontainebleau, in France, (Chaux carlonatee quartzifere. H.), is a variety of rhombohedral Lime-haloide, mechanically mixed with sand. If crystal- lised, it assumes the form of the acute rhombohedron R + 1 . Slate-spar occurs in Saxony, Norway, and Corn- wall ; Pisolite near Laybach in Carniola, and at Carlsbad in Bohemia ; Anthracolite in Salzburg, &c. Most of the other varieties are so common, that it would be useless to enter here into greater detail. According to the observa- tions of Sir JAMES HALL, Mr BUCHOLZ, and others, car- bonate of lime may be converted by the application of a columnar composition round a central axis in the belemnite seems to depend upon a similar disposition of calcareous matter in the living animal, similar perhaps to the fibrous structure in the bone of sepia, perpendicular to the layers of which it consists. H. ORDER I. MACROTYPOUS L1ME-HALOIDE. 93 high degree of heat, into a cleavable mass of rhombohedral Lime-haloide, resembling saline marble. It is daily form- ing in the stalactites of limestone caves and in mines, where it has been observed in the Hartz, to cover the steps of old ladders. A remarkable instance of its deposition in a bottle of Saratoga water, has been mentioned in the Edin. Phil. Journ. Vol. VIII. p. 402. 5. Several varieties of the present species are usefully employed for various purposes, partly depending upon their mechanical, partly upon their chemical composition. Those used in sculpture, and in ornamental architecture, are called Marble, several varieties of which are celebrat- ed, and their localities well known. The different kinds of marble have been distinguished and denominated, and are prized, according to pureness, colour, delineation, trans- lucency, size of the component individuals, and of the blocks which may be obtained free from fissures and ble- mishes ; also according to the degree of polish they receive, &c. The more common or coarse varieties are used for the common purposes of building, also for paving streets. A peculiar variety of very fine grained compact limestone is used for plates in lithography. The best sort is found near Pappenheim and Sohlenhofen in Bavaria. Quick- lime mixed with sand, forms mortar ; it is also used as manure, and in several manufactures, as in the process of tanning, &c. Carbonic acid for chemical purposes is often obtained from chalk. Chalk, and in Switzerland also Rock- milk, are well known materials for writing and whitewash- ing. The present species is a valuable addition in several processes of melting ores, and in producing certain kinds of glass ; it is particularly useful in melting iron- ores. 3. MACROTYPOUS * LIME-HALOIDE. Dolomite (in part). JAM. Syst. Vol. II. p. 462. Macro- * From pimps long, and rvvoi the form (fundamental form.) 9£ PHYSIOGRAPHY. CLASS II. typous Lime-stone. Man. p. 65. Bitter-spar. Pearl- spar. Dolomite. Magnesian Limestone. PHILL. p. 163. 165. 166. Braunspath. Dolomit. Rautenspath (in part). WERN. Hoffm. H. B. III. 1 S. 48. 57. 60. Braunkalk. Bitterkalk. HAUSM. III. S. 947- 960. Bitterkalk (in part). DolomL. Braunkalk. LEONH. S. 579, &c. Chaux carbonate'e aluminifere. Ch. c. ferrifere perle'e. Ch. c. magne'sifere (in part). HAUY. Traite', T. II. p. 173. 175. 187. Ch. c. ferro-manga- ne'sifere (in part). Tabl. comp. p. 5. Ch. c. ferrifere, mangane'sifere rose, ferro-manganesif ere, magne'sifere. Trait^, 2de Ed. T. I. p. 418. 420. 421. 427. Fundamental form. Rhombohedron. R = 106° 15'. Vol. I. Fig. 7. R. G. a = V 2-0779. Simple forms R — i short, and ORDER I. BRACHYTYPOUS LIME-HALOIDE. 99 OBSERVATIONS. 1. The correctness of the natural-historical determina* tion of the present species is put beyond a doubt by the properties which it presents, particularly those contained in the character of the species. It has been for the first time distinguished from others in the Characteristic of the Natural History System, and more particularly from the va- rieties of Rhomb-spar with which it was formerly con- founded. It has since been noticed by several mineralo- gists. Perhaps there are among the number of minerals, at present called Dolomite, Rhomb-spar, Miemite, Gur* hofian, Bitter-spar, Brown-spar, Pearl-spar, &c., still con- tained the varieties of other species, like the following one, of which this is evident from the measures of its angles, specific gravity, hardness, and other characters. The es- tablishment of macrotypous, brachy typous, and paratomous Lime-haloide, as particular species (besides those which be- long to the following order), Must therefore be consider- ed only as a first attempt towards a more correct determi* nation of these species, the continuation and developement of which will not only spread more light upon the natural- historical genus in general, but also more particularly upon the chemical constitution of these species. 2. The present species contains carbonate of iron, and carbonate of magnesia. These two ingredients were found in it by Professor STRO METER. According to Mr BROOKE, they are to each other in the proportion of about 1-315 : 8-685 without a trace of lime. 3. The varieties of this species have always been found accompanying those called Rhomb-spar, of the preceding one ; and tire varieties of both of them are often mixed with each other, as is the case in the Rothen Kopf and Greiner mountains in the Zillerthal. 4. It occurs in various pkces in Salzburg, the Tyrol, and Switzerland, and has lately been discovered in very si- milar varieties, associated with the preceding species in Unst, one of the Shetland isles. 100 PHYSIOGRAPHY. CLASS n. 5. PARATOMOUS* LIME-HALOIDE. Ilohwand, rohe Wand, Rosszahn, Wandstein of the Sti- rian and Carinthian miners. Fundamental form. Rhombohedron. R = 106° 12'. Vol. I. Fig. 7. R. G. a = V 2-0825. Simple forms. R — QD (o) ; R — 1 (g) = 135° 54' ; R (P), Golrath, Stiria. Char, of Comb. Rhombohedral. Combinations. 1. R — GO. R. Sim. Fig. 111. Salzburg. 2. R — 1. R. Gastein, Salzburg. Cleavage. R, perfect. Fracture uneven. Sur- face ; R — oo rough ; R — 1 deeply striated parallel to the edges of combination with R. Lustre vitreous, slightly inclining to pearly. Co- lour, white, with various tints of grey, red, and brown. Streak white. Translucent, often very faintly. Brittle. Hardness=3-5...4-0. Sp. Gr. = 3-080, a white cleavable variety. Compound Varieties. Twin-crystals. 1. Axis of revolution perpendicular, face of composition parallel to one of the faces of R -|- oo. Fig. 134 ; this is also found in massive varieties (Golrath, Sti- ria). 2. Axis of revolution perpendicular, face of composition parallel to a face of R — 1, generally * From vetpa about, and riftvu I cleave ; cleavable parallel to the faces or the fundamental form. ORDER II. BRACHYTYPOUS PARACHROSE-BARYTE. 101 contained in parallel layers, and forming the striae of the rhombohedron R, obtained by cleavage, in the direction of the horizontal diagonals. Fig. 131. Massive: composition granular, individuals in most cases easily discernible ; often mixed with rhombo- hedral Lime-haloide.- Faces of composition uneven and rough. OBSERVATIONS. 1. The chemical constituents of this species are as yet unknown, at least as to their relative quantities. It con- tains, besides carbonate of lime, also carbonate of iron. It becomes black before the blowpipe, and acts upon the magnetic needle. In nitric acid it is soluble with a brisk effervescence. The colour is darkened on the surface, by being exposed to the air. 2. This species occurs in the Rathhausberg in Salzburg, upon beds in mica-slate, in many places upon the beds of brachytypous Parachrose-baryte, extending from Stiria all along the chain of the Alps, as in the Golrath, and at Eisenerz in Stiria, in Salzburg, &c. The compound Stirian varieties from the Raiding mountain near Vordernberg, and the Rothsol on the Veitschalpe, belong to a more re- cent class of rocks. 3. It forms an excellent addition in the process of melting iron-ores. OBDER II. BARYTE. GENUS I. PARACHROSE*-BARYTE. 1. BRACHYTYPOUS PARACHROSE-BARYTE. Sparry Iron. JAM. Syst. VoL II. p. 451. Rhomboidal * From v&itixtufft;*) change of colour. PHYSIOGRAPHY. CLASS 11. Sparry Iron. Man. p. 61. Spathose Iron. Carbonate of Iron. Brown Spar. PHILL. p. 236. Spatheisenstein. WERN. Hoffm. H. B. III. 2. S. 262. Eisenkalk. Sphtirosiderit. HAUSM. III. S. 951. 1070. Kohlen- saures Eisen. L.EONH. S. 360. Chaux carbonatee ferrifere. HAUY. Traite, T. II. p. 175. Fer oxide- carbonate'. Tabl. comp. p. 99. Traite, 2de Ed. T. IV. p. 113. Fundamental form. Rhombohedron. R = 107° 0'. Vol.I. Fig. 7. R.G. a = V 2-0093. Simple forms. R — 00(0); R — 1 (g) - 136° 34', R (P) Pfaffenberg, Hartz. R -f 1 (/) = 80° 5', Tavystock, Devonshire ; | R + 2 (s) — 67° 52', Wheal Maudlin, Cornwall ; R + OD (c) ; P + QD (U). Char of Comb. Rhombohedral. Combinations. l.'R — go. R. Sim. Fig. 111. Przibram, Bohemia. %. R — 1. R. Rathhausberg, Salzburg. 3. R. R. + x. Sim. Fig. 114, the faces c very small. Przibram. 4. R. P + as. Sim. Fig. 118. Cornwall. 5. R — oo. R. J R + 2. Cornwall. Cleavage. R, perfect. Seldom traces of R — 1. Fracture imperfect conchoidal. Surface. R — QD generally rough ; R often round- ed, which terminates in the saddle shaped lens. Vol. I. Fig. 79, ; R — 1 streaked parallel to the edges of combination with R ; R + oo smooth, P 4- oo rough, | R + 2 often uneven and OBDERII. BRACHYTYPOUSPARACHROSE-BARYTE. 103 rounded. The common lens is produced by continued striae between R — 1 and R. Lustre, vitreous inclining to pearly. Colour vari- ous shades of yellowish-grey, passing into ash- and greenish-grey, also into several kinds of yellow, white, and red. Streak white. Trans- lucent, in different degrees. Brittle. Hardness = 3-5. . .4-5. Sp. Gr. = 3-829, a crystallised variety from Pfaffenberg in Anhalt. Compound Varieties. Striae upon the faces of R, in the direction of the horizontal diagonals, and faces of composition parallel to R — — 1, as in the preceding species, shew that there is also here regu- lar composition according to the same law. Botry- oidal and globular shapes : composition columnar ; surface drusy. Massive: composition granular, pass- ing into impalpable. OBSERVATIONS. 1. The massive varieties of the present species are often regularly compound in the direction of the faces of R — 1, as in Fig. 131. It is sometimes possible to obtain from them by fracture, the form of R — 1, bounded on all sides by faces of composition, without presenting a single real face of cleavage. There is no distinct cleavage parallel to the faces of R — 1 . The saddle-shaped lenses are in part composed of several individuals nearly in parallel position, but the axes of which are slightly diverging. Also the curvature of faces of cleavage often originates in composi- tion. Vol. I. Fig. 80. Different opinions prevail among mineralogists in regard to the determination and classification of the present spe- cies. In the Wernerian system it forms an undivided species in his Iron-genus. It was formerly united by 104 PHYSIOGRAPHY. CLASS u. HAUY with the species of rhombohedral Lime-haloide, but is now exhibited as an appendix to Fer oxyde, the prismatic Iron-ore of the system followed in the present work. Some varieties, containing from 0-005 to 0-025 of carbonate of lime, are considered by Professor HAUSMANN in con- nexion with rhombohedral Lime-haloide, while others, without that admixture, form a particular substance, Spltcc- rosiderite, which name refers to the botryoidal and globular shapes, and the curved faces of cleavage. An accurate exa- mination of all the physical properties shews the dif- ficulties connected with the one and the other of these methods of considering the matter, and points out the way, upon which we arrive with perfect security at a correct de- termination of all the varieties which the species contains. Decomposed varieties of the present species have been con- sidered as belonging to prismatic Iron-ore. This, however, is contrary to the principles of Natural History. 2. Two varieties of this species, 1. the Sphaerosiderite, and 2. a cleavable variety from Neudorf in the Hartz, have yielded to KLAPROTH, Protoxide of Iron 1., 63-75 2., 57-50. Carbonic Acid 34-00 36-00. Oxide of Manganese 075 3-30. Lime 0-00 1-25. Magnesia 0-52 0-00. The chemical formula of brachytypous Parachrose-baryte is Fe C2, which expresses the ratio of protoxide of iron to carbonic acid = 61-47 : 38-53. Before the blowpipe it becomes black, and acts upon the magnetic needle, but does not melt. It colours glass of borax green. It is difficultly soluble, and effervesces but little in nitric acid, particularly if not reduced to powder. On being exposed to the air it is gradually decomposed ; first the colour of the surface be- comes brown or black, from which change of colour the name of the genus has been derived ; afterwards also the streak is changed into red or brown, hardness and specific gravity are diminished, and even the chemical constitution is altered, the whole being converted into hydrate of iron. ORDER II. BRACHYTYPOUS PARACHEOSE-BARYTE. 105 3. Frequently the present species is found along with compound varieties of rhombohedral Lime-haloide, upon beds in gneiss, mica slate, clay slate, and newer rocks ; sometimes with prismatic and rhombohedral Iron-ore, pris- matic Hal-baryte, and other species. It likewise occurs in metalliferous veins, accompanied by hexahedral Lead-glance, tetrahedral Copper-glance, hexahedral Iron-pyrites, pyra- midal Copper-pyrites, &c., and is not uncommon in that class of veins in primitive mountains, in which the mass of the vein consists chiefly of the constituent parts of the rocks themselves. It is more rarely met with in the cavi- ties of trap rocks. 4. The beds upon which the varieties of the present spe- cies are found in immense quantities in Stiria, Carinthia, 'and the bordering countries, form coherent tracts which extend along the chain of the Alps on one side into Austria, and on the other into Salzburg, Sec. The celebrated Erzberg near Eisenerz, is situated in one of them. In similar re- lations it seems to occur in Schmalkalden, Siegen, &c. In Anhalt large masses of this species occur in veins of very considerable size, traversing greywacke, and in this rock it seems also to occur in various other places of the Hartz, and in many other countries. At Freiberg it is found in silver veins. In the high mountains of Salzburg it is met with in minute crystals in narrow veins, along with rhombohedral Quartz, prismatic Talc -mica, &c. It is also found with Tin-ore, as at Ehrenfriedersdorf in Saxony, Wheal Maudlin, St Just, and other places in Corn '.vail. Brachytypous Parachrose-baryte is besides found in more or less considerable masses in Bohemia, Bayreuth, Wiirtemberg, Switzerland, France, Spain, and in many other countries. 5. In many of the above mentioned countries, particu- larly in Stiria and Carinthia, considerable quantities of cast and wrought iron are obtained from the species, but par- ticularly steel, for the production of which it is highly valuable. 106 PHYSIOGRAPHY. CLASS II. 2. MACROTYPOUS PARACHROSE-BARYTE. llhomboidal Red Manganese. JAM. Syst. Vol. II. p. 445. Man. p. 63. Carbonate of Manganese. PHILL. p. 246. Rother Braunstein. Braunspath (zum Theil). WEIIN. Hoffm. H. B. IV. S. 158. Rhodochrosit. HAUSM. III. S. 1081. Kohlerisaures Mangan. LEONH. S. 381. Manganese oxide rose silicifere amorphe. HAUY. Traite', T. IV. p. 248. Manganese oxide' carbonate. Tabl. comp. p. 111. Manganese carbonate, i Traite', 2de Ed. T. IV.. p. 272. Fundamental form. Rhombohedron. R = 106° 51'. Vol. I. Fig. 7. R. G. a = V 2-0229. Simple forms. R — 1 (g) = 136° 25'; R (P), Kapnik, Transylvania. Char, of Comb. Rhombohedral. Combinations. 1. R — 1. R. Freiberg, Saxony. Cleavage, R. Faint traces parallel to R — 1. Fracture uneven, imperfect conchoidal. Surface ; R — 1 deeply streaked parallel to the edges of combination with R. This produces lenticular crystals. R sometimes smooth, but more gene- rally curved, so as to give rise to saddle-shaped lenses. Vol. I. Fig. 79. Lustre vitreous inclining to pearly. Colour, va- rious shades of rose-red, partly inclining to brown. Streak white. Translucent, in different degrees. Brittle. Hardness = 3-5. Sp. Gr. = 3-592, the crystallised variety from Kapnik. Compound Varieties. Globular and botryoidal shapes : surface sometimes smooth, at other times rough ; composition columnar, often indistinct. ORDER II. MACROTYPOUSPARACHROSE-BARYTE. 107 Massive : composition granular, sometimes small and even impalpable, sometimes it is columnar. OBSERVATIONS. 1. The varieties of the present species have often been confounded with other minerals, one of which, too imper- fectly known to be yet received in the system, is enume- rated in the Appendix. Though these species will not in future be confounded if we attend to their charac- ters, yet they bear to each other a strong degree of re- semblance, which extends likewise to some of the follow- ing species. The genus Parachrose-baryte joins to that of Lime-haloide, and explains, by the great similarity of the species contained in both these genera, the differences in the opinions which have prevailed among mineralogists in spite of the marked distinction among their characteristic, properties. 2. A variety of the present species has been found by Du ME NIL to consist of Oxide of Manganese 54-60. Carbonic Acid 3375. Oxide of Iron 1-87- Silica 4-37. Lime 2-50. In its pure state it is represented by Mn C2, which ex- presses 62-35 oxide of manganese, and 37-65 carbonic acid. It effervesces rather briskly in nitric acid ; before the blow-pipe its colour is changed into grey, brown, and black, and it decrepitates strongly, but is infusible without addition. It is easily soluble in glass of borax, which be- comes violet-blue. If exposed to the air, its natural colour is changed into brown. Many bright rose-red varieties become paler on being exposed in a similar manner. 3. The varieties of the present species occur generally in metalliferous veins, with various ores of silver and lead, also with Copper-pyrites and Iron-pyrites, rhombohedral Quartz, &c. They have likewise been found in beds in 108 PHYSIOGRAPHY. CLASS 11. transition mountains, with other minerals containing man- ganese. 4. It is frequently found in several of the Saxon mines, particularly in the neighbourhood of Freiberg, also at Nagy- ag and Kapnik in Transylvania, near Elbingerode in the Hartz, and in other countries. GENUS II. ZINC-BARYTE. 1. PRISMATIC ZINC-BARYTE. Prismatic Calamine or Electric Calamine. JAM. Vol. II. p. 437. Man. p. 65. Siliceous Oxide of Zinc. Electric Calamine. PHILL. p. 254. Galmei (in part). WERN. Hoffm. H. B. IV. 1. S. 90. Zinkglas. HAUSM. I. S. 343. Galmei. LEONH. S. 316. Zinc oxide'. HAUV. Traite', T. IV. p. 159. Tabl. comp. p. 102. Zinc oxide' silici- fere. Traite', 2de Ed. T. IV. p. 175. Fundamental form. Scalene four-sided pyramid P = 132° y, 101° 9', 97° 47. Vol. I, Fig! 9. AP. a : b : c = 1 : V2*628 : V1<072- Simple forms. P — oo (K) ; P (P) ; (P)5 ; (p — 1)4 . (pr + 00)5 (j) - 7go T . pr __ i (0 = 128° 27; | Pr + 1 (m) = 69° U' ; Pr + oo 0) ; Pr (c) = 116° 40' ; f Pr + 2 (p) = 56° 46'. Char, of Comb. Prismatic. Different faces conti- guous to the opposite ends of crystals. Combinations. 1. Pr. (Pr -f oo)3. Pr -f OD. Sim. Fig. 8. Leadhills, Scotland. 2. pr — 1. (£r + op)5. Pr + oo. Sim. Fig. 9. Rossegg, Carinthia. 3. pr — 1. pr. I Pr + 2. (Pr + oo)3. Pr -|- oo. Rezbanya, Hungary. 4. P — OD. Pr— 1. Pr. |Pr+l. | OttDER II. PRISMATIC ZINC-BARYTE. 109 (Pr + oo)3. Pr + oo. P. Fig. 37. A I- tenberg near Aix la Chapelle. Cleavage, Pr and (1?r -j- oc)5, both easily obtain- ed, the latter highly perfect. Traces of P — x. Fracture uneven. Surface of Pr -f oo and (Pr -j- oo)3 streaked parallel to their common intersections. The rest of the faces generally smooth : sometimes rounded, particularly P — QD. Lustre vitreous, inclining to pearly upon Pr + oc, sometimes to adamantine upon curved faces of crystallisation. Colour white, prevalent. Occa- sionally blue, green, yellow or brown. Streak white. Transparent ... translucent. Brittle. Hardness — 5-0. Sp. Gr. = 3-379, crystals from Rossegg in Carinthia. Compound Varieties. Globular, botryoidal shapes : surface drusy, composition columnar. Massive : composition either granular or columnar; the former of them often impalpable, and strongly coherent, and then the fracture becomes uneven ; the latter straight and divergent. OBSERVATIONS. 1. Among the forms quoted above, only Var. 4. Fig. 37. has been observed on both ends, which have presented that remarkable dissimilarity of configuration. In the others, the figures to which they are referred, suppose the two apices to be similar. The species of prismatic Zinc-ba- ryte affords another example of the co-existence of a dif- ferent configuration of the opposite summits, with dif- ferent kinds of electricity. The latter has been long ago observed; it is excited by the common changes of 110 PHYSIOGRAPHY. CLASS IJ. temperature, and is said to remain even after having ex- . posed the crystals to a red heat. The union of this and the following species within a single one, which formerly took place in almost all mine- ralogical systems, and even now continues in some of them, is at present gradually giving way. The impossibi- lity of uniting in one series rhombohedral and prismatic forms, or the degrees of specific gravity of the two .sub- stances, would each of them be a sufficient motive for ef- fecting this separation. 2. The varieties of the present species consist of Oxide of Zinc 66-00. 66.37. Silica 25-00. 26-23. Water 9-00. BERTHIEH. 7-40. BERZELIUS. Its chemical formula is Zn3 Si2 + 3 Aq, which corresponds exactly to the numbers given in the analysis by BERZELIUS. Reduced to powder, it is soluble in heated sulphuric or mu- riatic acid, and when cooled it forms a jelly. Before the blowpipe it decrepitates a little, loses its transparency, intumesces, and emits a green phosphorescent light. It is infusible without addition, but is dissolved by borax into a clear glassy globule, which becomes opake on cooling. It is phosphorescent by friction. 3. The present and the following species are frequently found accompanying each other in veins, and particularly in beds belonging to various classes of rocks, but chiefly calcareous ones. They are often associated with hexahe- dral Lead-glance, dodecahedral Garnet-blende, and some varieties of Iron-ores. 4. Considerable quantities occur at Bleiberg and Raibel in Carinthia, Rezbanya in Hungary, Freiburg in Brisgaw, Altenberg near Aix-la Chapelle, near Tarnowitz in Silesia, at Olkuzk and Medziana Gora in Poland, in Siberia, &c. It occurs in Leicestershire, Derbyshire, Flintshire, Somer- setshire, &c. in England, at Wanlockhead and Leadhills- in Scotland, and other places. ORDER II, RHOMBOHEDRAL ZINC-BARYTE. Ill 2. RHOMBOHEDRAL ZINC-BARYTE. Rhombohedral Calamine. JAM. Syst. Vol. II. p. 440. Man. p. 66. Carbonate of Zinc. Calamine. P;, ILL. p. 355. Galmei (in part). WERN. Hoffm. H. B. IV. 1. S. 96. Galmei. HAUSM. 1. S. 345. Zinkspath. LEOXH. S. 315. Zinc carbonate'. HAUY. Traite', T. IV. p. 164. TabL corap. p. 103. Traite', 2de Ed. T. IV. p. 181. Fundamental form. Rhombohedron. R =r 107° 4 rather perfect ; Pr 4- 1 less easily obtained. Faint traces of cleavage ob- servable in the direction of Pr -f- oo, or at least small conchoidal fracture. Fracture in other directions uneven. Surface, P — oo often rough, though even, and streaked parallel to the edges of combinations with Pr -f 1. P -|- oo deeply streaked in a horizontal direction, and hence often curved (barrel-shaped prisms). The py- ramids and horizontal prisms smooth ; P some- times streaked parallel to its obtuse terminal edges. Lustre vitreous, slightly inclining to resinous upon the uneven faces of fracture. Colour asparagus- green and apple-green ; pale yellowish-brown, yellow and grey ; white. Streak white. Trans- parent ... translucent. Brittle. Hardness = 3-5. Sp. Gr. = 3-605, the variety in acicular crystals from Braunsdorf near Freiberg. 118 PHYSIOGRAPHY. CLASS H. Compound Varieties. Twin crystals : axis of revolution perpendicular, face of composition paral- lel to a face of P -f- oo. The individuals generally continued beyond the face of composition. This composition is very similar to some that occur in prismatic Lime-haloide. The product of it is a six- sided prism, having four edges of 117° 19' and two of 128° 22'. As in the above mentioned species, particles of the two individuals alternate in parallel layers with each other. Indistinct globular masses : surface drusy, composition columnar. Massive : composition columnar, the individuals generally straight, long, and a little divergent ; the compo- sition is seldom granular. OBSERVATIONS. 1. KLAPROTH found a variety of the present species to consist of Strontia 69-50. Carbonic Acid 30-00. Water 0-50. It is Sr C2, which corresponds to 70-16 of Strontia, and 29-84 Carbonic acid. It is soluble with effervescence in the muriatic and nitric acids ; and paper, dipped into this solution and afterwards dried, will burn with a red flame. It melts before the blowpipe at a temperature not very elevated, but only on the thinnest edges. It intumesces, and spreads a brilliant light ; the flame at the same time assumes a reddish hue. It is dissolved by borax with a violent effervescence into a clear globule, 2. The repositories of this species of Hal-baryte are me- tallic veins traversing primitive and transition mountains either containing hexahedral Lead-glance, prismatic Hal- baryte, &c. or prismatic Arsenical-pyrites, rhombohedral Quartz, and other species. It seems also to occur in beds. OfiDER II. DI-PRISMATIC HAL-UAllYTE. 119 3. It was first discovered at Strontian in Argyleshire in Scotland, and found afterwards at Braunsdorf in Saxony, in large crystals at Leogang in Salzburg, and also in Peru* 2. DI-PEISMATIC HAL-BAEYTE. Rhomboidal Baryte or Witherite. JAM. Syst. Vol. II. p. 394. Di-prismatic Baryte or Witherite. Man. p. 70. Witherite. Carbonate of Barytes. PHILL. p. 182. Witherit. WERN. Hoffm. H. B. III. 1. S. 150. Wi- therit. HAUSM. III. S. 1004. Kohlensaurer Baryt. LEOSTH. S. 613. Baryte carbonate'e. HAUY. Traite', T. II. p. 308. Tabl. conip. n, 13. Traite', 2de Ed. T. II. p. 25. Fundamental form. Scalene four-sided pyramid, of unknown dimensions. Vol. I. Fig. 9. Simple forms. P — x (o) ; P ; P + oo (M ) = 118° 30' PHILL. ; Pr — 1 (x) ; f r (P); £ r + 1 (*) * ; Pr + oo (h). Char, of Comb. Prismatic. Combinations. 1. Pr. P -f- oo. P r -}- oo. Sim. Fig. 9. 2. P. Pr + 1. P+ oo. fr + oo. 3. P — CD. P. Pr+1. P -I- oo. Pr -f 00. 4. p r — 1. Pr. Pr-f-1. P + x. Pr + oo. Sim. Fig. S3. All of them from Anglesark, Lancashire. Cleavage. Pr + oo, P -f- x and Pr + 1, imper- fect ; the last of these difficultly observed. Frac- ture uneven, Surface of P + oo horizontally * Inclination of these prisms to £r + co = 110° 30', 126° 16', and 145° 30', according to PHILLIPS. H. 120 PHYSIOGRAPHY. CLASS II. streaked ; that of P r + 1 parallel to the edges of combination with P. Lustre vitreous, inclining to resinous. The latter more distinct in the fracture. Colour white, ge- nerally yellowish, approaching to orange-yellow ; sometimes passing into various shades of grey. Streak white. Semi-transparent ... translucent. Brittle. Hardness = 3-0 . . . 3-5. Sp. Gr. = 4-301, a white semi-transparent cleavable variety. Compound Varieties. Twin-crystals : axis of re- volution perpendicular, face of composition parallel to a face of P + x. The individuals continued beyond it, as in the preceding species. Globular, tuberose, reniform, botryoidal shapes : surface rough, uneven, and drusy ; composition granular, often strongly coherent. Massive : composition either granular, or columnar ; more frequently the latter. Sometimes multifarious composition. OBSERVATIONS. 1. According to BUCHOLZ, the di-prismatic Hal-baryte consists of Baryta 79-66. Carbonic Acid 20-00. Water 0-33. Its chemical formula is Ba C2, which corresponds to 77'66 of baryta, and 22-34 of carbonic acid. Before the blow- pipe it decrepitates slightly, and melts easily into a trans- parent bead, which loses its transparency on cooling. It is soluble with effervescence in dilute nitric or muriatic acid. 2. It occurs in veins traversing limestone, which rests upon red sandstone, and alternates with sandstone, slaty clay and coal seams, accompanied by prismatic Hal-ba- ODDER II. PRISMATIC HAL-BARYTE. ryte, which generally occurs in the higher parts of the veins, hexahedral Lead-glance and dodecahedral Garnet- blende, with several Lime-haloides, and other species ; it is also found in lead-veins traversing greywacke, and in irregular beds along with paratomous Lime-haloide in clay slate. 3. Large quantities of this species are found in England, in the counties of Durham, Westmoreland, Lancaster, and Salop, in veins ; also near Neuberg in Stiria in irregular beds. It has been mentioned from Hungary, Salzburg, Siberia, Sicily, and other places, where it seems to occur only in small quantities. 4. It is a violent poison, and has been used in several parts of England for killing rats. 3. PRISMATIC HAL-BARYTE. Prismatic Baryte or Heavy-spar. .JAM. Syst. Vol. II. p, 398. Man. p. 71. Heavy spar. Sulphate of Barytes. PHILL. p. 183. Schwerspath. WERN. Hoffm. H. B. III. 1. S. 155. Baryt. Hepatit. HAUSM. III. S. 991. 1000. Schwefelsaurer Baryt. LEONH. S. 606. Baryte sulfate'e. HAUY. Traite', T. II. p. 295. TabL comp. p. 12. Traite', 2de Ed. T. II. p. 5. Fundamental form. Scalene four-sided pyramid. P = 128° 23', 91° 2(f, 110° 44'. Vol. I. Fig. 9. R. G. a : b : c = 1 : V1'7045 : J0662?. Simple forms. P — OD (&); P (2); P + QD (n) = 106° ?' ; (P)3 = 69° 9'* ; (P + . Sim. Fig. 17. Montecchio near Vicenza. 4. Pr. Pr. (?r — I)3. Pr + oo. Lengthened in the direction of the edges between Pr and ?r H- oo. Ghibesa, Sicily. 5. Pr. Pr. P. (?r + oo)3. Pr -f- QD. Sim. Fig. 21. Lengthened in the same direction. Bex, Switzerland. 6. Pr. (Pr — I)3. Pr. P. (Pr + )5. f r -f QD. Pr + QD. Fig. 169. Leadhills.* Cleavage. Pr and (Pr + oo)5 often perfect, gene- rally interrupted by conchoidal fracture. Traces of Pr + OD and (Pr -f- oo)3. Fracture conchoi- dal. Surface, P sometimes streaked parallel to the edges of combination with (?r -J- x)5 or with Pr ; Pr + cc almost always streaked, ver- tically and at the same time also horizontally, the latter however less deeply. Lustre adamantine passing into resinous. The former is often metallic, if the colours be dark. Very thin crystals, and columnar compositions of them often possess pearly lustre. Colour white prevalent, passing into yellowish-grey, ash-grey, and smoke-grey, or even into greyish-black. Sometimes tinged green or blue by several spe- cies of the order Malachite. Streak white. Transparent ... translucent Rather brittle. Hardness = 3-0... 3-5. Sp. Gr. = 6-465 of a white translucent variety. Compound Varieties. Twin-crystals: axis of * A crystal of this form is preserved in the collection of Mr ALLAN. H. 132 PHYSIOGRAPHY. CLASS II. revolution perpendicular, face of composition par- allel to one of the faces of Pr. The composition is often repeated, not only in parallel laminae, as in prismatic Lime-haloide, but likewise parallel to both the faces of ?r. The individuals are generally con- tinued beyond the face of composition. Thus are formed the well known star-like compound crystals of the present species, as represented in Fig. 38. Massive : composition often granular, or even impal- pable, and strongly connected ; more rarely co- lumnar. Faces of composition rough, or longitu- dinally or irregularly streaked. OBSERVATIONS. 1. The species distinguished by mineralogists within the varieties of di-prismatic Lead-baryte, are White Lead-Spar, Black Lead-Spar, and Earthy Lead-Spar. The last of these comprehends impalpable compositions, often mixed with clay, silica, oxide of iron, &c., and thence variously co- loured. It is farther named indurated or friable, agreeably to the state of coherence of its particles. The other two are distinguished only in colour, so that those whose colour is not black are called white lead-spar, while the rest forms the Hack lead-spar. The varieties of the latter are gene- rally less perfectly formed than those of the former, which, like the colour, seems to be a consequence of mere acciden- tal circumstances in their formation. 2. A variety of the present species has yielded to KLAP- ROTH, Oxide of Lead 82-00. Carbonic Acid 16-00. Water 2-00. It is expressed by the formula Pb C2, which corresponds to 83-52 oxide of lead, and 16-48 carbonic acid. The black varieties are said to contain a small proportion of carbon. ORDER II. DI-PRISMATIC LEAD-BARYTE. 133 It effervesces in dilute nitric acid, and is easily soluble. Before the blowpipe it decrepitates and changes its colour into yellow and red ; if properly managed, it yields a glo- bule of metallic lead. Reduced to powder and thrown upon ignited charcoal, it emits a phosphorescent light. 3. Among the species of the present geniis the di-pris- matic Lead-baryte is that most commonly found in nature. It occurs in veins and beds in various classes of rocks, ac- companied chiefly by hexahedral Lead-glance, several spe- cies of Baryte and Malachite, Iron-pyrites, dodecahedral Garnet-blende, octahedral Fluor-haloide, and other species. Crystallised varieties are more generally found in higher levels of veins, like other species of the present genus. 4. Beautiful crystallised and other varieties of the di- prismatic Lead-baryte are found in various mining dis- tricts of Saxony, particularly at Johanngeorgenstadt ; at Clausthal and Zellerfeld in the Hartz ; at Freiburg in Brisgaw; at Tarnowitz in Silesia; at Mies, Przibram, and other places in Bohemia, at Bleiberg in Carinthia, in France, and many other countries of the European conti- nent. Splendid crystals have been brought from the Daurian mountains in Siberia, on the frontiers of China ; fine varieties are found at Wanlockhead and Leadhills in Scotland, in the mines of Cumberland and Durham, at Wheal Crenver in Cornwall, &c. The localities of Black Lead-spar are Freiberg and Zschopau in Saxony, and LeadhiUs in Scotland. Earthy Lead-spar occurs in Poland, Silesia, Siberia, in the district of Eiffel in Germany, &c. 5. If found in considerable quantities, the present spe- cies is usefully employed as an ore of lead. It is the most important species in this respect after the hexahedral Lead-glance, with which it generally is found and melted together. 2. RHOMBOHEDRAL LEAD-BARYTE. Rhomboidal Lead-Spar. JAM. Syst. Vol. II. p. 369. 85. Phosphate of Lead. Arseniate of Lead. 134 PHYSIOGRAPHY. CLASS II. PniLL.p. 344. 345. Braunbleierz. Griinbleierz. WERN. Hoffm. H. B. IV. 1. S. 15. 27. Pyromorphit. Trau- blenblei. HAUSM. III. S. 1090. 1093. Phosphorsaures Blei. LEONH. S. 236. Ploinb phosphate. HAUY. Trait^, T. III. p. 490. Tabl. comp. p. 82. Traite, 2de Ed. T. III. p. 385. Fundamental form. Rhombohedron. R — 88° 29'. Vol. I. Fig. 7. R. G. Simple forms. R — 00(0); R; — R; R-|- oo (g) ; P (P. s) = 142° 1%, 80° 44'; P + 1 ; P + 2; P -f oo (»). Char, of Comb. Di-rhombohedral. 2 (R) = 131° 5', 111° 48'. Combinations. 1. R — oo. P -f- oo. Przibram, Bohemia. 2. R— oo. P. P + oo. Sim. Fig. 118. Zschop- au. Saxony. 3. R — oo. P. R -f oo. P+oo. Freiburg, Baden. Cleavage. P imperfect and interrupted. Traces of P -f- oo. Fracture imperfect conchoidal, un- even. Surface, P+oo almost always horizon- tally streaked, and often uneven. Owing to these striae, the prisms are often barrel-shaped, or contracted at the ends of the prisms. R — oo rough, and often excavated. Lustre resinous. Colour, generally green or brown. There is an uninterrupted series from various shades of white through siskin-green, asparagus- green, grass-green, pistachio-green, olive-green, oil-green ; wax-yellow, honey-yellow, orange- ORDER II. BHOMBOHEJDBAL LEAD-BARYTE. 135 yellow ; aurora-red, hyacinth-red ; hair-brown, clove-brown ; pearl-grey and ash-grey. Streak white, sometimes inclining to yellow. Semi- transparent... translucent on the edges. Brittle. Hardness = 3-5 . . . 4-0. Sp. Gr. = 7'098, of a green variety from Zschopau. Compound Varieties. Globular, reniform, bo- tryoidal, fruticose shapes: composition columnar; faces of composition rough, irregularly streaked, seldom smooth. Massive : composition columnar, or granular ; the latter in most cases strongly coherent. OBSERVATIONS. 1. The preceding general description refers to the va- rieties in which phosphate of lead has been found to form the greatest proportion in the constituent parts. The angles were measured in minute splendent crystals, of a green colour from Brisgaw, a variety of which the specific gravity is given = 6-9111 by HAUY. The variety from Johanngeorgenstadt in Saxony, which consists of arseniate of lead, yielded by measurement the lateral edge of the py- ramid P = 79° 40', from which the terminal edge follows = 1423 39', and a == ^4-696. It seems therefore that it will be necessary in future to consider it as a particular species, different from rhombohedral Lead-baryte. The crystalline varieties are much the same in both these sub- stances ; thus P. P +.os, (Fig. 117.)> and R — «. P. 2 (R). R + CD. P + os have been found at Johanngeor- genstadt. The faces 2(R) are uneven, and P + 1, and particularly P + os, which occur in the same variety, are rough. Twin crystals have been found joined in a face perpendicular to one of the terminal edges of P. The specific gravity is = 7'208. 136 PHYSIOGRAPHY. CLASS n. Formerly two species used to be distinguished, the Green and Brown Lead-Spar, merely according to the shades of colours, which, however, as in rhombohedral Emerald, or other well determined species, form but one uninter- rupted species, in which only arbitrary limits can be fixed. Green Lead-spar referred to varieties of green or greenish colours, while Brown Lead-spar comprehended those in which the colours approached more to brown tints. What has been called Blue Lead possesses the shape of the crys- tals of the present species, the substance of which has been replaced by hexahedral Lead-glance. There are varieties of Blue Lead, which consist of rhombohedral Lead-baryte of a dark blueish-grey colour. 2. In two varieties, one of a brown colour from Huel- goet, the other a green one from Zschopau in Saxony, KLAPROTH found the following ingredients : Oxide of Lead 78-58 78-40. Phosphoric Acid 1973 18-37. Muriatic Acid 1-65 1-70. Oxide of Iron 0-00 0-10. The proportion of oxide of lead and phosporic acid, cor- responding to the formula Pb5 P4, is that of 79-27 : 20-73. Two specimens containing arsenic acid, yielded to ROSE, Oxide of Lead 77'50 77'50. Phosphoric Acid 0-00 7*50. Arsenic Acid 19-00 12-50. Muriatic Acid 1-53 1-50. Oxide of Iron 0-25 0-00. The rhombohedral Lead-baryte is soluble without efferves- cence in heated nitric acid. Before the blowpipe it melts by itself upon charcoal, and the bead assumes a polyhedral form of a dark colour. In the interior flame the globule becomes blueish, in the moment of crystallisation it is lu- minous, and the faces become larger. The form itself has not been accurately examined ; it seems to consist of several crystalline individuals. 3. The varieties of the present species occur chiefly ORDER II. HEMI-PRISMATIC LEAD-BARYTE. 137 in veins, particularly in their higher levels, in various rocks, but they are also found in beds. Upon veins they are accompanied by hexahedral Lead-glance, and various species of the genus Lead-bary te, by prismatic Hal-bary te, dodecahedral Garnet-blende, octahedral Fluor-haloide, rhombohedral Quartz, &c. ; sometimes also by different ores of silver, &c. 4. Finely crystallised and other varieties are found at Zschopau and other places in Saxony, Przibram, and Mies in Bohemia, Freiburg in the Brisgaw, in Hungary, in the Hartz, at Poullaouen and Huelgoet in Brittany, at Lead- hills and "SVanlockhead in Scotland, in Cornwall, and in several counties of the north of England. The finest crystallised varieties of the arseniate of lead occur at Johanngeorgenstadt in Saxony, in silver veins. 3. HEMI-PRISMATIC LEAD-BARYTE. Prismatic Lead-Spar, or lied Lead-Spar. JAM. Syst. Vol. II. p. 3C6. Hemi-prismatic Lead-Spar,- or Red Lead-Spar. Man. p. 87- Chromate of Lead. PHILL. p. 349. Rothbleierz. WERK. Hoffm. H. B. IV. 1. S. 33. Kallochrom. HAUSM. III. S. 10G4. Chromsaures Blei. LEOKH. S. 246. Plomb chromate. HAUV. Traite', T. III. p. 467. Tabl. comp. p. 81. Traite7, 2de Ed. T. III. p. 357. SORET. Ann. des Mines. T. III. p. 481. Fundamental form. Scalene four-sided pyramid. P = {{^I g£}, 109°. 37, 105° 45'. Inclina- tion of the axis = 12° 3(X in the plane of the short diagonal. Vol. I. Fig. 41. AP. a : b : c : d = 4-52 : 4-82 : 5-02 : 1. Simpleforms. P- P + CD (M) = 93° 40'; — ; (Pr + c*) VOL. II. 138 PHYSIOGRAPHY. CLASS H. = 56° 7; (Pr + oo)* r=129°40'*; ± Pr - V ; Pr + 1 (y) = 58° 3',; fr -f QD fe). Char, of Comb. Hemi-prismatic. Inclination of P — oo on Pr + x = 102° 20', of P — oo on P + oo = 99° 11'. Combinations. 1. ^. P+ oo. (£r+ oo)4. HAUY. 2. |. --- Fig. 5S. ?. Pr. Pr + 1. -Lr. -L - P + x. (Pr + oo)3. Pr + 00. Pr + oo. Fig. 170. f All of them from Beresof. Cleavage. P + CD, pretty easily observable, ?r -f- oo and Pr -f- oo indistinct. None of them perfect. Fracture small conchoidal, uneven. Surface, the prisms parallel the axis streaked in the direction of * Four-sided prisms of C4° 36' and of 120° 41' are quoted by Messrs HAUY and SORET. They are represented by. the ns (£r + co)< and (Pr + w)«. H. -t- In the cabinet of Mr ALLAX. H. ORDER II. HEMI-PRISMATIC LEAD-BARYTE. 139 •p that line, often very considerably ; - sometimes 9S faintly streaked parallel to the edges of combina- Pr 4- 2 tion with P -f- x ; — — — generally curved. The faces are almost always smooth and shining. Lustre adamantine. Colour, various shades of hy- acinth red. Streak orange-yellow. Translucent, sometimes only on the edges. Sectile. Hardness = 2-5 ... 3-0. Sp. Gr. = 6-004. Compound Varieties. Massive : composition im- perfect columnar or granular. OBSERVATIONS. 1. According to PFAFF, the hemi-prismatic Lead-baryta consists of Oxide of Lead 68-00. Chromic Acid 32-00. Its chemical formula is Pb Ch, agreeing with 68-15 of oxide of lead, and 31-85 of chromic acid. Before the blow- pipe it becomes black and decrepitates if quickly heated ; it may be melted, however, into a shining slag, containing globules of metallic lead. It colours glass of borax green, is soluble without effervescence in nitric acid, and pro- duces a yellow solution. 2. It has been found particularly in Siberia, where it oc- curs in the neighbourhood of Beresof, in narrow veins, traversing a rock, the true nature of which is not yet known, accompanied by hexahedral crystals of Iron-pyrites, generally in a state of decomposition, also by hexahedral Lead-glance, rhombohedral and di-prismatic Lead-baryte, sometimes also by hexahedral Gold. In Brazil it is met with in sandstone, probably under similar circumstances. 140 PHYSIOGRAPHY. CLASS H. 4. PYRAMIDAL LEAD-BARYTE. Pyramidal Lead-Spar. JAM. Syst. Vol. II. p. 362. Man. p. 88. Molybdate of Lead. PHILL. p. 348. Gelb- bleierz. WERN. Hoffm. H. B. IV. 1. S. 36. Bleigelb. HAUSM. III. S. 1 101. Molybdansaures Blei. LEONH. S. 249. Plomb molybdate. HAUY. Traite, T. III. p. 498. Tabl. comp. p. 83. Traite', 2de Ed. T. III. p>397. Fundamental form. Isosceles four-sided pyramid. P = 99° 40', 131° 35'. Yol. I. Fig. 8. B, G. Simple forms. P — oo (a) ; P — 3 (c) = 128° 9', 76° 22' ; P — • 1 (e) = 106° 44', 115° 7' ; P(P), Bleiberg, Carinthia; ^ P — 3 (b) = 130° 11', 73° T ; ^ P — 2 (d) = 118° 26', 92° 43' ; P+ oo; [P+ oo]; [(P + 00)^]. Char, of Comb. Pyramidal. Combinations. 1. P — - cc. ^ P — 3. Fig. 92. Annaberg, Austria. 2. P — 137° °'* IncUnation of the axis = 0° 29' in the plane of the long dia- gonal. Vol. I. Fig. 41. HAIDINGER. a : b : c : d = 120 : 95 : 54-5 : 1. Simple forms. P— oo (a); ?LnJ: (i) = 147°23'; — 1 very perfect, and — — . Sur- face generally smooth and shining, some of the faces rough. It occurs also in twin-crystals. . Lustre adamantine. Co- lour deep and beautiful azure-blue. Streak pale-blue. Faintly translucent. Rather brittle. Hardness = 2 '5 ... 3-0. Sp. Gr. = 5-30 ... 5-43, BROOKE. It consists of 74'4 sulphate of lead, 18 'oxide of copper, and 4'7 water, according to Mr BROOKE. The locality of this species is Leadhills, where it occurs along with the pre- ceding ones. It has also been found at Linares in Spain. It was discovered by Mr SOWERBY, and described as car- bonate of copper in his British Mineralogy ^ III. 5. iv. Corneous Lead. Corneous Lead. JAM. Syst. Vol. II. p. 388. Man. p. 468. Murio-carbonate of Lead. Pyramidal. Combinations like Fig. 101., having the sum- mit replaced by a plane perpendicular to the axis. Incli- nation of s to g = 135°, BROOKE. Cleavage parallel to P + os, cross-fracture conchoidal. Lustre adamantine. Co- lour white and pale tints of grey, yellow, and green. Streak white. Transparent... translucent. Rather sec tile. Hard- ness below 3-0, inferior to that of di-prismatic Lead-baryte. Sp. Gr. = 6-056, CHENEVIX. According to KLAPROTH it consists of 85-5 oxide of lead, 8-5 muriatic acid, and 6-0 carbonic acid. Before the blow- pipe it melts quickly into a yellow globule, which becomes white, and crystallises upon the surface, when cooling. Upon charcoal it is reduced. The localities of this mineral are Matlock in Derbyshire, Hausbaden near Badenweiler in Germany, and Southampton in Massachusetts, North America. It is found with other ores of lead, with octa- hedral Fluor-haloide, prismatic Hal-baryte, &c. OKDER II. miSMATIC AXTlMONY-liAKYTE. 151 v. Pentomous Lead-barytc. A new ore of lead. BERZELIUS. Ami. of Phil. XL.IV. p. 154. Edin. Journ. of Science, VoL I. p. 379. Prismatic. Cleavage highly perfect and easily obtained, parallel to a four-sided prism of 102° 27', and traces in the direction of its short diagonal. Traces of cleavage appa- rently parallel to a horizontal prism, having its axis paral- lel to the long diagonal of the vertical prism, HAIDINGER. Fracture imperfect conchoidal, uneven. Colour yellowish- white, straw-yellow, rose-red, pale. Lustre adamantine, particularly upon the cross-fracture, inclining to pearly upon faces of cleavage. Translucent. Rather brittle. Hardness = 2-5 ... 3-0. Sp. Gr. = 7*«77, HAIDINGER. It consists, according to BERZELIUS, of oxide of lead 90-13, muriatic acid 6-84, carbonic acid 1 -03, water 0-54, and silica 1-46. The carbonic acid in this and the preceding species are supposed by BERZELIUS to be accidental. He considers the present species as a compound of two atoms of oxide and one atom of chloride of lead, in the proportion of 38-28 to 61.72, while the preceding one contains one atom of each, and the ordinary artificial submuriate, one atom of chloride and three atoms of oxide of lead. It decrepitates slight- ly before the blow-pipe, and is easily melted ; the globule is of a deeper yellow than the mineral. On charcoal it is reduced, and emits fumes of muriatic acid. Treated with peroxide of copper and salt of phosphorus, the flame as- sumes an intense blue colour. It has been found near Churchhill, in the Mendip hills in Somersetshire, in ra- diated masses engaged in Manganese-ores, and accompanied by several other Lead-barytes and rhombohedral Lime-ha- loide. GENUS IV. ANTIMONY-BARYTE. 1. PRISMATIC ANTIMOXY-BARYTE. Prismatic White Antimony. JAM. Syst. Vol. II. p. 205. 152 PHYSIOGRAPHY. CLASS n. Man. p. 113. White Antimony. Oxide of Antimony. PHILL. p. 331. Weisspiesglaserz. WERN. Hoff'm. H. B. IV. 1. S. 119. Spiessglanzweiss. HAUSM. I. S. 341. Antimonbliithe. LEONH. S. 160. Antimoine oxide'. HAUY. Traite, T, IV. p. 273. Tabl. comp. p. 113. Traite, 2de Ed. T. IV. p. 308. Fundamental form. Scalene four-sided pyramid. P = 105° 38', 79° 44', 155° IT. Vol. I. Fig. 9. a : b : c = 10 : J12-5 : x/7'77- Simple forms. P (P) ; (Pr + cc) 3 (M) = 136° 58', R. G. ; Pr — 1 (p) = 70° 32', AP. Pr + oo. Char, of Comb. Prismatic. Combinations. 1. Pr — 1 . (Pr + oo) 3 . Pr+oo. Sim. Fig. 9. Braunsdorf, Saxony. 2. Pr — 1. P. (Pr+oo)3. Pr + oo. Fig. 14. Braunsdorf. Cleavage. (Pr -|- oo)3 highly perfect, and easily obtained. Scarcely traces parallel to Pr -f oo. Fracture not observable. Surface Pr — 1 and P curved ; Pr -|- oo smooth and even ; (Pr -{- oo) 3 very even, though sometimes a little rough. Lustre adamantine, particularly upon the curved faces, upon Pr -f- oo often pearly lustre. Co- lour white prevalent, passing into peach-blossom- red and ash-grey. Streak white. Semi-trans- parent ... translucent. Sectile. Hardness = 2-5 . . . 3-0. Sp. Gr. = 5-566, the simple crystals from Braunsdorf. Compound Varieties. Crystals, compressed be- tween Pr -f GO, are joined parallel to this face. If the individuals be very thin, the common varieties of this species are formed, which used to be consi- ORDER n. PRISMATIC ANTIMONY-BAEYTE. 153 dered as simple forms, and the faces of composition as faces of cleavage with a pearly lustre. In trying the experiment of ascertaining their hardness, we must be careful, on account of the crystals being very fragile. Massive : composition granular, la- mellar, columnar ; faces of composition of the gra- nular individuals in general irregularly streaked. OBSERVATIONS. 1. The present species I formerly included in the order Mica, as prismatic Antimony-mica. Owing to the com- pound state of the then known varieties, among others those from Przibram, and which was considered as cleavage, the true cleavage has long been overlooked, and the hardness examined in the same varieties indicated as less consider- able than it is in nature. Simple varieties of the species have since been found at Braunsdorf near Freiberg, which yielded the characters indicated above, and which have even served to simplify the Characteristic. 2. According to VAUQUELIN, the present species con- sists of Oxide of Antimony 86-00. Oxide of Antimony and Iron 3-00. Silica 8-00. It is pure oxide of antimony, s'b, according to BERZELIUS, equal to 84-32 of metal, and 15-68 of oxygen. It is soluble in nitro-muriatic acid. It melts at the flame of a candle. Before the blowpipe, upon charcoal, it is en- tirely volatilised, and produces a white coating upon the support. It is frequently produced during chemical ope- rations, and crystallised from sublimation. If metallic an- timony is melted before the blowpipe, it emits fumes which crystallise round the globule, and at last cover it entirely. First yellowish octahedral crystals, probably of antimo- nious acid, are formed, and then a beautiful tissue of acicu- lar prisms of oxide of antimony. They are sufficiently PHYSIOGRAPHY. CLASS i|. thin to reflect green and red colours, but admit neverthe- less of being measured by means of the reflective gonio- meter. 3. It occurs in small quantities in veins, traversing pri- mitive or grey wacke rocks, associated with ores of lead and antimony, with dodecahedral Garnet-blende, rhombohedral Lime-haloide, and very often rhombohedral Quartz. 4. Beautiful, though generally compound varieties of aggregated tabular crystals, have been found at Przibram in Bohemia, prisms of considerable thickness at Braunsdorf in Saxony. It is found also at Malaczka in Hungary, in Baden, in Nassau, and at Allemont in Dauphiny. ORDER III. KERATE. I. PEARL-KERATE. 1. HEXAHEDRAL PEARL-KERATE. Hexahedral Corneous Silver. JAM. Syst. Vol. II. p. 350. Man. p. 90. Muriate of Silver. Horn Silver. PHILL. p. 295. Hornerz. WERN. Hoffm. II. B. III. 2. S. 51. Hornsilber. HAUSM. III. p. 1010. Silber-Hornerz. L.EONH. S. 208. Argent muriate. HAIJY. Traite', T. III. p. 418. Tabl. comp. p. 75. Traite, 2de Ed. T. III. p. 292. Fundamental form. Hexahedron. Vol.1. Fig. 1. Simple forms. H, Johanngeorgenstadt, Saxony ; 6, Vol. I. Fig. 2., Siberia; D, Vol. I. Fig. 31. Siberia. Char, of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4. Wheal Mexico, Cornwall. 2. H, D. Fig. 151. Johanngeorgenstadt. Cleavage none. Fracture more or less perfect con- phoidal. Surface of the hexahedron sometimes ORDER HI. HEXAHEDRAL 1'E ARL-KERATE. 155 faintly streaked parallel to the edges of combi- nation with the dodecahedron. Lustre resinous, passing into adamantine. Faces of fracture often more splendent than those of crystallisation. Colour pearl-grey, passing on one hand into lavender-blue and violet-blue, on the other into greyish-, yellowish-, and greenish- white, into siskin-green, asparagus-green, pista- chio-green, and leek-green. The colour becomes brown on being exposed to light. Streak shining. Translucent... feebly translucent on the edges. Sectile. Hardness = 1-0 ... 1-5. Sp. Gr. = 5-552, a white granular variety from Peru. Compound Varieties. In crusts: composition scarcely observable, sometimes columnar. Mas- sive : composition granular, strongly coherent, or imperfect columnar, and often bent ; faces of com- position rough. OBSERVATIONS. 1. KLAPHOTH found two varieties of the present species, one from Saxony, and the other from Peru, to consist of Silver 6775 76-0. Oxygen 6-?5 7'6. Muriatic Acid 14-75 16-4. Oxide of Iron 6-00 0-0. Alumina 1'75 0-0. Sulphuric Acid 0-25 0-0. The formula for its chemical composition is Ag M2, or 80-903 oxide of silver and 29-097 muriatic acid. It is fusible in the flame of a candle, and emits fumes of muriatic acid. Upon charcoal it may be almost entirely reduced before the blowpipe, and is likewise easily reduced if rubbed wet upon PHYSIOGRAPHY. CLASS II. a clean surface of iron or zinc. It is insoluble in nitric acid or in water. It may be obtained in a crystallised state, either from fusion, or from the evaporation of a solution of muriate of silver in ammonia. 2. The present species is most frequently found in the upper parts of veins in clay-slate, but occurs also in beds, generally along with other ores of silver, very often also with ochry varieties of prismatic Iron-ore, or with similar varieties of decomposed Iron-pyrites. Sometimes, though as it seems not in veins, hexahedral Gold is found accom- panying it. It is associated also with several species of the orders Malachite, Pyrites, Haloide, Baryte, &c. 3. Formerly it occurred in considerable quantities in the Saxon mining districts of Johanngeorgenstadt and Frei- berg ; also at Joachimsthal in Bohemia. In small quanti- ties it is found in France, in Spain, at Kongsberg in Nor- way, in Cornwall, and Siberia ; but in large masses, fre- quently associated with hexahedral silver, in Mexico and Peru, where particularly the green varieties of colours occur. 4. It is used for extracting silver. $. PYRAMIDAL PEARL-K.ERATK. Pyramidal Corneous Mercury. JAM. Syst. Vol. II. p. 356. Man. p. 91. Muriate of Mercury. PHILL. p. 359. Quecksilber-Hornerz. WERN. Hoffm. H. B. III. 2. S. 25. Hornquecksilber. HAUSM. III. S. 1017. Quecksilber- Hornerz. LEONH. S. 191. Mercure muriate. HAUY, Traite', T. III. p. 447. Tabl. comp. 78. Traite', 2de Ed. T. III. p. 331. Fundamental form. Isosceles four-sided pyramid. P = 98° 4', 136° V. Vol. I. Fig. 8. BROOKE. Simple forms. -^- P — 3 (a) = 138° IV, 60° 1 1' ; -^ P — 2 (c1) ; P (c2) = 126° 31', 79° 3'; Char, of Comb. Pyramidal. Combinations. 1. P. [P + oo]. Sim. Fig. 97. ORDER in. PYRAMIDAL PEARL-KER ATE. 157 2. i^-ip—S. ^P — 2. P + oo. [P + oo). Sim. Fig. 102. Cleavage P + OD very indistinct. Fracture perfect conchoidal. Surface smooth. Lustre adamantine. Colour yellowish-grey or ash- grey, also yellowish- and greyish-white. Streak white. Translucent, sometimes only on the edges. Sectile. Hardness = 1-0...2-0. Sp. Gr. - 6 482. Compound Varieties. Crystalline coats, proba- bly formed originally upon globules of fluid mer- cury : composition not observable. Massive : com- position granular. OBSERVATIONS. 1. The mixture of pyramidal Pearl- Kerate is expressed by Hg M , which corresponds to Oxide of Mercury 88-48. Muriatic Acid 11-52. Before the blowpipe, upon charcoal, it is entirely volati- lised, if pure. According to GMELIN, it is not soluble in water. 2. This rare mineral occurs in the repositories of peri- toraous Ruby-blende in secondary rocks, sometimes upon veins of Iron-ore ; it is accompanied by various ores of mercury, also by ocbry varieties of prismatic Iron-ore, &c. 3. Its chief locality is Moschellandsberg in Deuxponts, but it occurs also at Idria in Carniola, and Almaden in Spain. At Horzowitz in Bohemia it has been found with peritomous Ruby-blende in veins traversing a bed of Iron- ore. 158 PHYSIOGRAPHY. CLASS II. . MALACHITE. GENUS I. STAPHYL1NE*-MALACHITE. 1. UNCLEAVABLE STAPHYLINE-MALACHITE. Common Copper-Green or Chrysocolla. JAM. Syst. Vol. II. p. 305. Uncleavable Copper-Green. Man. p. 92. Chrysocolla. PHILL. p. 312. Kupfergrlin. Eisenchussig Kupfergrun. WERN. Hoffm. H. B. III. 2. S. 152. 155. Kieselmalachit. HAUSM. III. S. 1029. Kiesel-Kupfer. L.EOVH. S. 289. Cuivre carbonate' vert (in part). HAU v. Traite', T. III. p. 571. Cuivre carbonate vert terreux. Tabl. comp. p. 90. Cuivre hydrosiliceux ou Cuivre hy- drate siliceux (in part). Traite, 2deEd. T. III. p. 471. Regular forms unknown. Cleavage none. Frac- ture conchoidal. Colour, emerald-green, pistachio-green, asparagus- green, passing into sky-blue. If they incline to brown, the mineral is impure. Streak white, a little shining. Semi-transparent ... translucent on the edges. Rather sectile. Hardness = 2-0 ... 3-0. Sp. Gr. = 2-031, a semi-transparent variety. Compound Varieties. Botryoidal, reniform shapes or massive varieties : composition impalpable ; frac- t ure more or less perfectly conchoidal. Pseudo- morphoses in the shape of octahedral Copper-ore, rhombohedral Euchlore-mica, &c. Impure va- rieties are often earthy. * From retQvXvi, the grape. The varieties hitherto know n generally present botryoidal shapes. ORDER IV. UXCLEAVABLE STAPHYLINE-MAL. 159 OBSERVATIONS. 1. Copper-Green and Ironshot Copper-Green^ into which the varieties of the present species used formerly to be distin- guished, differ in nothing but the greater or less pureness of their substance. The latter of these, comprehending the dark-coloured and brown varieties, was again sub- divided into tlaggy and earthy ironshot copper-green, the one firm, and presenting a conchoidal fracture, the other earthy, and of a friable consistency. Some mineralogists unite the earthy varieties with the hemi-prismatic Habro- neme-malachite, from which some of them may possibly derive their existence, and formerly all the varieties of it were comprehended by some within that species. 2. Two analyses, one by KLAPROTH, another by JOHN, have yielded Copper 40-00 42-00. Oxygen 10-00 7-63. Silica 26-00 28-37- Water 17'00 17'50. Carbonic Acid 7-00 3-00. Sulphate of Lime 0-00 1-50. Before the blowpipe upon charcoal it first becomes black, in the inner flame red, without melting. Vv'ith borax it melts into a green glassy globule, and is partly reduced, as the metallic particles shew, which this globule contains. If pure it is soluble without effervescence in nitric acid, and leaves a residue of silica. 3. The natural repositories of the present species are those of other ores of copper, where it is found along with them ; and also with ochry varieties of prismatic Iron-ore, prismatic Hal-baryte, rhombohedral Quartz, &c. 4. It occurs at Saalfeld in Thuringia, at Lauterberg in the Hartz, at Saska and Moldawa in the Bannat, at Her- rengrund in Lower Hungary, at Falkenstein and Schwa t^ in the Tyrol, in the Lizard district in Cornwall, in Nor- way, Siberia, Mexico, and ChilL 160 PHYSIOGRAPHY. CLASS II. 5. Where it occurs in sufficient quantity, it is used for extracting copper. 6. The only author who quotes crystals of the present species is the Abbe' HAUY (Traite, 2de Ed. T. III. p. 471., and Traite de Cryst. T. II. p. 577.). Crystals of this spe- cies in fact may occur ; yet those which he describes cer- tainly cannot be varieties of it, if they possess a specific gravity = 2 '733. The forms are described as being pris- matic, in which the ratio of the lines a : b : c is = 1 : 2 : A/ 2-5, the observed simple forms, P — cc (P) ; P + co (M) = 103° 20'; Pr (1) = 120° 52'; Pr (rf) = 115° 22' ; Pr + os (/•), and the combinations: 1. Pr. P + os. Sim. Fig. 2. ; 2. P _ cc. P + co. Pr + cc ; 3. Pr. P + co. Pr + co. Sim. Fig. 9. Cleavage is said to take place pa- rallel to P + co. The crystals are from Catharinenburg in Siberia, and Very rare. The natural-historical determination of a species, besides a knowledge of its forms, requires also the accurate investi- gation of hardness and specific gravity. The latter does not agree with that of uncleavable Staphy line-malachite ; the former has been passed over in silence. Much is therefore still wanting for a complete determination of the species to which the crystals belong, which have been described. GENUS II. LIROCONE*-MALACHITE. 1. PRISMATIC LIROCONE-MALACHITE. Di-prismatic Olivenite or Lenticular Copper. JAM. Syst. Vol. II. p. 333. Prismatic Liriconite. Man. p. 94. Octahedral Arseniate of Copper. PHILL. p. 316. Lin- senerz. WERN. Hoffin. H. B. III. 2. S. 165. Linsen- kupfer. HAUSM. III. S. 1051. Linsenerz. LEONH. S. 282. Cuivre arse'niate' primitif. HAUY. Tabl. comp. p. 90. Cuivre arse'niate octaedre obtus. "Traite', 2de Ed. T. III. p. 509. From x 17. 18. Combinations, 1. H. -. 2. H. 1. 3. H. °. 5. 4. H. ° D.5.-5. 22 222 Cleavage. Hexahedron, difficult and imperfect. Fracture conchoidal, uneven. Surface of the hexahedron sometimes streaked parallel to the edges of combinations with the tetrahedron. The ORDER IV. HEXAHEDR AL LIROCONE-MALACH1TE. 163 other faces, with exception of the dodecahedron, often curved. Lustre adamantine, not very distinct. Colour olive-green, passing into yellowish-brown bor- dering sometimes upon hyacinth-red and blackish- brown ; also into grass-green and emerald-green. Streak olive-green ... brown, commonly pale. Translucent on the edges. Rather sectile. Hardness = 2-5. Sp, Gr. = 3-000, BOUEXON. Compound Varieties. Massive : composition granular, rare. OBSERVATIONS 1. The hexahedral Lirocone-malachite consists of Oxide of Iron 45-50 48-00. Arsenic 31-00 18-00. Oxide of Copper 9-00 0-00. Silica 4-00 0-00. Carbonate of Lime 0-00 2-00. Water 10-50 CHENEVIX. 32-00. VAUQUELIK. Exposed to a gentle heat, its colour is changed into red. In a higher degree of temperature it intumesces, gives little or no arsenic, and leaves a red powder. Upon char- coal it emits copious fumes of arsenic, and melts in the inner flame into a metallic scoria, which acts upon the magnetic needle. 2. The chief repositories of this Malachite are veins of copper ores in the older classes of rocks, where it is ac- companied by prismatic Copper-glance and pyramidal Cop- per-pyrites, by prismatic Iron-ore, often in ochrey varieties, and by rhombohedral Quartz. 3. It is principally found in Cornwall, in several copper- mines in the neighbourhood of Redruth ; but has been PHYSIOGRAPHY. CLASS II. found also at St Leonhard in France, and at Schwarzen- berg in Saxony. GENUS III. OLIVE-MALACHITE. 1. PRISMATIC OLIVE-MALACHITE. Acicular Olivenite. JAM. Syst. Vol. II. p. 335. Pris- matic Olivenite, (excepting the first sub-species) Man. p. 96. Right Prismatic Arseniate of Copper. PHILL. p. 31 9. Olivenerz. WERN. Hoffm.-H. B. III. 2. S. 170. Olivenkupfer. HAUSM. III. S. 1045. Olivenit. LEONH. S. 283. Cuivre arseniat^ (in part). HAUY. Traite', T. III. p. 575. Cuivre arseniate' octaedre aigu. Tabl. comp. p. 91. Traite, 2de Ed. T. III. p. 510. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Simple forms. P + oo (r) = 92° 30', PHILL. ; Pr (1) = 1 10° 50', PHILL. ; Pr + oo (n) ; Pr -f oo. Char, of Comb. Prismatic. Combinations. 1. Pr. P + oo. Pr + o>. Fig. 8. 2, Pr. P -h oo. Pr + QD. Pr + QD. Cleavage. Traces parallel to Pr and P -f oo, the former being a little more distinct. Fracture conchoidal, uneven. Surface, Pr and Pr -J- oo concave, P -h oo convex, the faces parallel to the axis being curved in the direction of the same line. At the same time uneven. Pr + QD very smooth and even. Lustre adamantine, indistinct. Colour, various shades of olive-green, passing into leek-green, pistachio-green and blackish-green, into liver- brown and wood-brown, or also into siskin-green. 6RDERIV. PRISMATIC OLIVE-MALACHITi:. 165 Streak olive-green ... brown. Semi-transparent ... opake. Brittle. Hardness = 3-0. Sp. Gr. = 4-2809. BODRNON. Compound Varieties. Globular and reniform shapes : surface rough, sometimes drusy ; composi- tion columnar, generally very perfect, straight and divergent, rarely promiscuous. If the composition be very thin, the lustre becomes pearly. Massive : composition columnar. Sometimes repeated com- position ; granular and columnar ; curved lamellar and columnar. The faces of the first composition rough, of the second composition smooth, OBSERVATIONS. 1. The prismatic Olive-malachite has been found to con- sist of Oxide of Copper 50-62 50-00. Arsenic Acid 45-00 29-00. Water 3-50 KLAPROTH. 21-00. CHENEVIX. Alone it remains unchanged before the blowpipe. Upon charcoal it melts, with a kind of deflagration, and is reduced. A white metallic globule is formed, which in the process of cooling becomes covered with a red coating of sub-oxide of copper. In some varieties a scoria is formed round the me- tallic globule. This mineral is soluble in nitric acid. 2. It is found in veins, chiefly consisting of various ores of copper and rhonibohedral Quartz. It is . accompanied by these, and by prismatic Iron-ore and decomposed Iron- pyrites. 3. It occurs in the copper mines near Redruth in Corn- wall, and has been lately discovered in Tynehead mine, near Alstonmoor iu Cumberland. 166 PHYSIOGRAPHY. CLASS II. 2. DI-PRISMATIC OLIVE-MALACHITE. Prismatic Olivenite, or Phosphate of Copper (in part). JAM. Syst. Vol. II. p. 331. Di-prismatip Olivenite. Man. p. 98. Phosphate of Copper. PHILL. p. 314. Olivenerz (in part). WERN. Hoffm. H. B. III. 2. S. 170. Blatt- riger Pseudomalachit (in partX HAUSM. III. S. 1036. Phosphorsaures Kupfer (in part). LEONH. S. 273. Cuivre phosphate' (in part). HAUY. Tabl. comp. p. 92. Traite', 2de Ed. T. III. p. 519. Fundamental form. Scalene four-sided pyramid. P = 122° 58', 117° 8', 89° 59'. Vol. I. Fig. 9. LEONH. a : b : c = 1 : V 2-194 : ^ 1'839- Simple forms. P (P) ; (ft)5. P + oo (u) = 95° 2' ; (Pr -f o>)5 = 130° 48' ; £ r (o) = 111° 58'. Char, of Comb. Prismatic. Combinations. 1. ?r. P -f CD. Sim. Fig. 2. 2. ft-. P. P -f OD. Fig. 5. Cleavage, indistinct traces parallel to ft and P -f oo. Fracture conchoidal, uneven. Surface of P very- smooth and even ; ft striated parallel to its edges of combination with P, P -f QD in a vertical di- rection, often uneven. Lustre resinous. Colour olive-green, generally dark. Streak olive-green. Translucent on the edges. Brittle. Hardness = 4-0. Sp. Gr. = 3-6 ... 8-8. OBSERVATIONS. 1. According to BDCHOLZ, the present species consists of phosphate of copper ; but no accurate analysis of it has yet been published. Mineralogists are not entirely agreed respecting its classification. Some unite it with the pre- ceding species, others with the prismatic Habroneme- ORDEH IV. PRISMATIC AZURE-MALACHITE. 167 malachite. Even though we should not pay attention to the geometrical characters, hardness and specific gravity would be sufficient for their distinction. 2. It occurs engaged in cavities of rhombohedral Quartz, and associated with pyramidal Copper-pyrites, in a bed in primitive rocks, at Libethen near Neusohl in Hungary ; also at Gunnislake in Cornwall. GENUS IV. AZURE-MALACHITE. 1. PRISMATIC AZURE-MALACHITE. Blue Copper or Prismatic Malachite. JAM. Syst. Vol. II* p. 313. Prismatic Blue Malachite. Man. p. 98. Blue Carbonate of Copper. PHILL. p. 309. Kupferlasur. WERX. Hoffm. H. B. III. 2. S. 134. Kupferlasur. HAUSM. III. S. 1020. Kohlensaures Kupfer (in part). LEONH. S. 276. Cuivre carbonate' bleu. HAU Y. Traite', T. III. p. 562. Tabl. comp. p. 89. Cuivre carbonate' (in part). Traite, 2de Ed. T. lit. p. 488. CORDIER. Ann. des Mines. Vol. IV. p. 3. Fundamental form. Scalene four-sided pyramid. {llfio >jr\ 118° 16'}' 107° ^ 104° T' Inclination of the axis = 2° 21' in the plane of the short diagonal. Vol. I. Fig. 41. R. G. a : b : c : d = 24-30 : 25-25 : 28'70 : 1. C- 1 f T> /\ PJ*l /116° 7' I Simple forms P — QD (s); -f_-— 4.J = 1 113° jfi'j ; P + 00 (/) = 97° 24'; - (-^-^' (*); + )5 (P) = 59° 14'; (fr + ; fr — 1 (g) = 134° 7' ; Pr (M) = 99° 3^; 168 rHYSIOGllAI'liy. CLASS * Pr — 1 iv (66° 12' » Pr ftr+oo; + — Char, of Comb. Hemi-prismatic. Inclination of p — x to Pr -f oo = 87° 39'. Combinations. 1. Pr. Pr -f oo. Chessy, France. 2. Pr. — (Pr — !)•> pr + ^ Chessy. 3. P — oo. &L^i2)-.. (Pr -f oo)3. Pr + oo. 8 Fig. 63. Bannat. 4. P _ QD. £5. I. Pr. - g g Pr -f QD. Fig. 64. Chessy. 5. P— QD. —. Pr. — ^JTli. — (Pr + oo)3. (Pr + oo)5. Pr + oo. Fig. 65. Chessy. r p Pr P (Pr — 1)' (ftr— !) T 8" ~2~ "" (Pr -f- x)5. (Pr + x)5. Pr + oo. Fig. 66. Chessy. Cleavage. (Pr -f oo)5 perfect, but interrupted by conchoidal fracture. Less distinct, P — CD ; imperfect in the direction of Pr. Fracture con- choidal. Surface, P — OD sometimes streaked parallel to the edges of combination with ORDER IV. PRISMATIC AZURE-MALACHITE. 169 Pr -f co, Pr + OD parallel to those with P — oo or also with P -f oo. The faces of some of the forms, as of _J_-TT__5 and of 1_L~ L. rough. Pr -f- oo sometimes concave, the greater part of the other faces even and smooth. Lustre vitreous, almost adamantine. Colour vari- ous shades of azure-blue, passing into blackish- blue and berlin-blue. Streak blue, lighter than the colour. Transparent ... translucent on, the edges. Brittle. Hardness = 3-5... 4-0. Sp. Gr. = 3-831, crystals from Chessy. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendi- Pr cular to — * Globular, reniform, botryoidal, stalactitic shapes, implanted and imbedded : surface drusy and rough ; composition columnar, more or less perfect and distinct, faces of composition generally rough. Massive : composition columnar, more rarely granular. Sometimes there is another curved lamellar composition, the curved faces of which often possess a darker colour than the rest, and are covered with asperities. Rarely in an earthy state. * A beautiful specimen of this rare variety is preserved in the cabinet of Mr ALLAX. 170 PHYSIOGEAPHY. CLASS II. OBSERVATIONS. 1. From a comparison of the general description given of the present species and of hemi-prismatic Habroneme- malachite, or even from that of their characters, as given in the Characteristic, it appears that they cannot be united within one and the same species, as has been done by se- veral celebrated mineralogists, who founded their opinion chiefly on the agreement of the chemical analyses. In other respects, the present and the former determinations differ only in regard to. the establishment of Earthy Blue Copper into a particular sub-species, and the division of the rest of the varieties, or the Radiated Blue Copper^ according to their mechanical composition. 2. Two analyses of the present species, one by KLAP- ROTH, the other by VAUQUELIN-, have yielded Copper 56-00 56-00. Oxygen 14-00 12-50. Carbonic Acid 24-00 25-00. Water 6-00 6-50. Its chemical formula is Cu Aq2 + 2 Cu C2, corresponding to 69-16 oxide of copper, 25-61 carbonic acid, and 5-23 of water. It is soluble with effervescence in nitric acid, be- comes black if exposed alone to high degrees of tempera- ture, melts upon charcoal, and colours glass of borax green in the oxidating flame. 3. It is met with in veins and beds, included in rocks of different ages. It is generally accompanied by other ores of copper, and among these principally by hemi-prismatic Habroneme-malachite, with which it is often intimately connected, so that crystals of the form of the 'present spe- cies, consist entirely, or at least with only the exception of a thin film on the surface, of the delicate green fibres of the hemi-prismatic Habroneme-malachite. It is often en- gaged in ochrey varieties of prismatic Iron-ore, and asso- ciated with di-prismatic Lead-baryte, sometimes with hexa- hedral Lead glance, and prismatic Cobalt-mica ; besides also with prismatic Hal-baryte, rhombohedral Quartz, rhombo- ORDER IV. BHOMBOHEDRAL EMERALD-HAL. 171 hedral Lime-haloide, &c. In veins it is generally found in the higher levels. 4. Most beautiful varieties, particularly crystallised ones, have lately been found in a bed in secondary mountains at Chessy near Lyons in France. Also in Siberia, very fine crystals have been obtained. Those from the Bannat, though of a smaller size, are often very distinct. Fine crystallised varieties occur at Wheal Buller, near Redruth in Cornwall. Prismatic Azure-malachite occurs, besides, at Saalfeld in Thuringia, in Mansfeld, in Hessia, in "Wur- temberg, in the Hartz, in Silesia, at Schwatz in the Tyrol, in Spain, Chili, &c. The earthy blue copper is chiefly known from Thuringia, Hessia, and from the Hartz. 5. Wherever it occurs in sufficient quantities, it is an useful mineral for extracting copper. GENUS V. EMERALD-MALACHITE. 1. RHOMBOHEDRAL EMERALD-MALACHITE. Rhombohedral Emerald Copper or Dioptase. JAM. Svst. Vol. II. p. 347. Rhomboidal Emerald-Malachite. Man. p. 100. Dioptase. Emerald Copper. PHILL. p. 312. Kupfersmaragd. WERX. Hoffm. H. B. III. 2. S. 158. Dioptas. HAUSM. III. S. 1032. Kupfer- Smaragd. LEONH. S. 288. Dioptase. HAUY. Trait^, T. III. p. 136. Cuivre dioptase. TabL comp. p. 91. Traite, 2de Ed. T. III. p. 477- Fundamental form. Rhombohedron. R = 126° 17'. Vol. I. Fig. 7. PHILL. a = V 0-8413. Simple forms. R + 1 (r) = 95° 48' ; P + oo (s). Char of Comb. Rhombohedral, as to the simple forms observed, but the striae upon the faces of R seem to indicate a hemi-rhombohedral cha- racter. Combination. 1. R. P + oo. Fig. 118. PHYSIOGRAPHY. 'CLASS ll. Cleavage. R, perfect. Fracture conchoidal, un- even. Surface streaked parallel to the edges of combination, inclined upon R, either to the right or to the left. Lustre vitreous inclining to resinous. Colour, emerald-green, also blackish -green, and verdi- gris-green. Streak green. Transparent... trans- lucent. Brittle. Hardness = 5-0. Sp. Gr. = 3-278. OBSERVATIONS. 1. Two analyses, one by LOWITZ, another by VAUQUE- LIN, have yielded, Oxide of Copper 55-00 25-57. Carbonate of Lime 0-00 42-85. Silica 33-00 28-57. Water 12-00 0-00. It decrepitates before the blowpipe, and upon charcoal it becomes black in the exterior flame, and red in the interior one, without melting. It is easily soluble in glass of borax, and imparts to it a green colour. It is soluble without ef- fervescence in muriatic acid. 2. It has been found accompanied by hemi-prismatic Ilabroneme-malachite and rhombohedral Lime-haloide, but the nature of its original repositories is not known. It oc- curs in the Kirghese steppes, from whence it was brought by ACHIR MEHEMET, a Buchanan merchant, and named in consequence Achirite. According to Mr PHILLIPS, it oc- curs in minute crystals with the prismatic Zinc-baryte from Rezbanya in Hungary. OKJDERIV. PRISMATIC HABRONEME-MALACHITH. 173 GEKUS VI. HABRONEME "-MALACHITE. 1. PRISMATIC HABRONEME-MALACHITE. Prismatic Olivenite or Phosphate of Copper. JAM. Syst. Vol. II. p. 331. Prismatic Green Malachite. Man. p. 101. Hydrous Phosphate of Copper. PHILL. p. 315. Phosphorkupfererz (in part). WERIT. Hoffm. H. B. III. 2. S. 183. Pseudomalachit. HAUSM. III. S. 1036. Phosphorsaures Kupfer (in part). L.EONH. S. 273. Cuivre phosphate (in part). HAUY. TabL comp. p. 90. Trait^, 2de Ed. T. III. p. 519. Fundamental form. Scalene four-sided pyramid. P = 117° 49^ 137° 1(X, 101° 32'. Inclination of the axis. in the plane of the long diagonal = 0. Vol. I. Fig. 41. AP. a : b : C : d = 2 : 3/2 : 3 : 0. Simple forms. P — oo (a); ?. (P) = 117° 4^; 8 — ^l^- (d) ; (Pr + oc)5 (f) = 38° 56' ; f76°34'K Pr -H oo (e). Char, of Comb. Hemi-prismatic. p Combinations. 1. P — oo. — (Pr -}- oo)5. 2. P— x. ^r~"1. -. (Pr+09)5. Pr+oo. 3.P-00. ?^L.\. P. -?L^1. • From «/V9f, delicate, and vJy**, the thread or fibre. 174 PHYSIOGRAPHY. CLASS II. — > ~_.L. (Pr -f oc)3. Pr + oo. Fig. 71. All of them from the Rhine. Pr — 1 Cleavage. Slight indications parallel to — and Pr -j- oo. Fracture small conchoidal, un- p even. Surface P — oo and _ a little rough, though even ; (Pr + oo)5 smooth and uneven, — ( ' curved, the rest of the faces smooth and even. Lustre adamantine, inclining to vitreous. Colour, emerald-green, verdigris-green, blackish-green, often darker on the surface. Streak green, a little paler than the colour. Translucent, often only on the edges. Brittle. Hardness = 4-5 ...5-0. Sp. Gr. = 4-205, a crystallised variety from Rheinbreitbach near Bonn. Compound Varieties. Reniform, rather imper- fect : composition imperfect columnar ; surface drusy, and often of a darker colour. Massive : composition as above. OBSERVATIONS. 1. Formerly the varieties of di-prismatic Olive-mala- chite were confounded with the present species, as has been observed above (p. 166). Count BOURNON gives the angle of the prism P + oo = 110°, according to the pre- ceding dimensions it would be = 109° 28'. Yet the angles ORDEB IV. HEMI-PBISMATIC HABRONEME-MAL. 175 require perhaps some correction from admeasurements of better pronounced crystals. Those to which the above description refers, are preserved in the Wernerian collec- tion at Freiberg. Messrs LEVY, PHILLIPS, and BROOKE, have also observed the hemiprismatic character of com- binations. Mr BROOKE gives the angle of the prism (Pr + co)3 = 37° 30', but likewise from imperfect crystals. 2. Two analyses of the variety from the Rhine have yielded, Oxide of Copper 68-13 62-847. Phosphoric Acid 30-95 21-687- Water 0-00 KLAPROTH. 15-454. LUNK. Ed. Ph. Journ. VoL V. p. 213. Before the blowpipe it melts and boils easily, and is con- verted into a small vesicular metalloidal globule. It is soluble without effervescence in nitric acid, particularly if heated. 3. The prismatic Habroneme-makchite is found in veins traversing greywacke slate, and is accompanied by several varieties of rhombohedral Quartz, and ores of copper, as in the Virneberg near Rheinbreitbach on the Rhine. 2. HEMI-PEISMATIC HABRONEME-MALACHITE. Malachite. JAM. Syst. Vol. II. p. 321. Di-prismatic Green Malachite or Common Malachite. Man. p. 102. Green Carbonate of Copper. PHILL. p. 310. Mala- chit. WERK. Hoffm. H. B. III. 2. S. 144. Malachit. HAUSM. III. S. 1025. Kohlensaures Kupfer (in part). L.EONH. S. 276. Cuivre carbonate' vert. HAUY. Traite\ T. III. p. 571. Tabl. comp. p. 90. Cuivre carbonate' (in part). Traite', 2de Ed. T. III. p. 488. Fundamental form. Scalene four-sided pyramid. P = 139° IT, 127° 25', 68° 33'. Inclination of the axis in the plane of the short diagonal = 0. Vol. I. Fig. 41. AP. a : b : c : d = I : 5-64 : / 3-48 : 0 176 PHYSIOGRAPHY. CLASS II. Simple forms. P — OD ; - = 139° IT ; P + oo (M) =103° 42'; — ?^ (p) = 61° 49'; Pr 4 oo (s). Char, of Comb. Hemi-prismatic. Combinations. 1. P — oo. P 4- oo. Pr -f oo. Chessy. 2. — ?!. P — OD. Pr + oo. Chessy. rfV 3. P — op. — . P -f oo. Pr -f a?. Chessy. 52 Cleavage. Highly perfect in the direction of — — and of Pr 4 OD, the former, however, • still more easily obtained. Fracture conchoidal, uneven, scarcely observable in crystallised va- p rieties. Surface, P — oo rough ; -curved; Pr 4 GO sometimes vertically streaked. The rest of the faces smooth. Lustre adamantine, inclining to vitreous. Colour grass-green, emerald-green, verdigris-green. Streak green, rather paler than the colour. Translucent, sometimes only on the edges. Brittle. Hardness = 3-5 ... 4-0. Sp. Gr. = 4-008 a cleavable variety from Chessy. Com/pound Varieties. Twin crystals : axis of revolution perpendicular, face of composition paral- lel to Pr 4 oo. Fig. 78. This composition occurs ORDER iv. HEMI-PRISMATIC HABKOXEMK-MAL. 177 in almost every variety, and even in those masses which consist of columnar particles of composition. It then seems as if both the faces belonging to a horizontal prism were present, forming a dihedral termination of each individual, of 123° 37', while in fact there exists only one of them. Fascicular aggregations of delicate crystals. Tuberose, globu- lar, reniform, botryoidal, and stalactitic shapes : surface drusy, rough, sometimes smooth ; compo- sition columnar, generally very thin, often impalp- able. Very thin columnar composition produces a satiny lustre ; impalpable composition is the cause of conchoidal fracture. Massive : composition as above. The composition is often repeated ; granu- larly compound masses consist of columnar ones ra- diating from a centre ; curved lamellar ones are likewise composed of thin columnar individuals. The surface of the second composition is often rough, and particularly in curved lamellar compo- sitions, covered with a white coating. OBSERVATION'S. 1. The species of Malachite has been divided into fibrous and compact Malachite. If the columnar particles of com- position decrease in size, the fibrous Malachite is gradually converted into compact Malachite, which therefore is al- ways a compound mineral. These two kinds pass insen- sibly into each other, and it is often difficult to tell, to which of them a specimen occurring in nature should be referred. 2. Two analyses of hemi-prismatic Habroneme-malachite, one by KLAPBOTH, and another by VATTQUF.I.IV, have yielded, VOL. II. M 178 PHYSIOGRAPHY. CLASS II- Copper 58-00 56-10. Oxygen 12-50 14-00. Carbonic Acid 18-00 21-25. Water 1 1-50 8-75. Its chemical formula is Cu C + Aq, which requires 71-886 oxide of copper, 19-962 carbonic acid, and 8-208 water. It is soluble without residue in nitric acid. Before the blowpipe it decrepitates, becomes black, and is partly infu- sible, partly converted into a black scoria. It is easily dis- solved in glass of borax, imparts to it a deep green colour, and yields a globule of metallic copper. 3. It occurs in the same repositories as prismatic Azure- malachite, by which it is often accompanied. Beautiful varieties of fibrous Malachite are found at Chessy in France, in Siberia, and at Moldawa in the Bannat of Te- meswar; the compact Malachite is chiefly known from Schwatz in the Tyrol. It occurs, besides, in small quan- tities in Cornwall, Wales, and various other countries. 4. Several varieties, that are sufficiently compact, are cut into vases, snuff-boxes, ring-stones, and other orna- ments. Others are used as pigments. If it occurs in con- siderable quantities, it is a valuable ore for extracting copper. ORDER V. MICA. GENUS I. EUCHLORE*-MICA. 1. RHOMBOHEDRAL EUCHLORE-MICA. Prismatic Copper Mica. JAM. Syst. Vol. II. p. 184. Hemi-prismatic Copper-Mica. Man. p. 106. Rhom- boidal Arseniate of Copper. PHILL. p. 317. Kupfer- glimmer. WERN. Hoffm. H. B. III. S. 162. Kupfer- glimmer. HAUSM. III. S. 1043. Kupferglimmer. From jtf#A«$fl$, bright, lively green. ORDER v. BHOMBOHEDRAL EUCHLORE-MICA. 179 LEONH. S. 286. Cuivre arseniate lamelliforme. HAU Y. Traite, T. III. p. 578. TabL comp. p. 90. Cuivre arseniate hexagonal lamelliforme. Traite*, 2de Ed. T. III. p. 509. BROOKE. Ed. Phil. Journ. Vol. VI. p. 132. Fundamental form. Rhombohedron. R = 68° 45'. Vol. I. Fig. 7. BROOKE. a = V22-26. Simple forms. R — oo (o) ; R (R) ; P + oo. Char, of Comb. Rhombohedral. Combinations. 1. R — QD. R. Fig. 119. Ting- tang, Cornwall. 2. R — QD. R. R + oo. Tingtang. Cleavage. R — QD highly perfect. Traces of R. Fracture conchoidal, scarcely observable. Sur- face, R — QD smooth, sometimes striated in tri- angular directions. R often a little uneven. Lustre pearly upon R — QD, both as faces of cleav- age, and as faces of crystallisation. The faces R possess a lustre intermediate between vitreous and adamantine. Colour emerald-green, grass- green. Streak emerald-green ... apple-green^ rather paler than the colour. Transparent ... translucent. Sectile. Hardness = 20. Sp. Gr. = 2-5488, BOURNON. Compound Varieties. Massive : composition gra- nular of various sizes of individuals j faces of com- position uneven and rough. OBSERVATIONS. 1. According to Mr BTJOOKE, the terminal edge of R is 180 , PHYSIOGRAPHY. CLASS IT. between 68° 38' and 68° 53', the mean term of which is 68° 45', as given above. Besides the forms mentioned there, he likewise indicates an obtuse rhombohedron, in parallel posi- tion with R, having a terminal edge of 1 79° 30', which posses- ses brilliant planes and sharp edges, but " is not easily re- duced to the common laws of decrement." Obtuse rhom- bohedrons of this kind, and also pyramids, occur in nature, but they have not yet been sufficiently described. They are easily explained upon the supposition of the series of forms existing in the crystalline series of a species. If we attend only to the principal series, we have R — 8 = 178° 47' in parallel position, R — 9 = 179° 23' in transverse position, R — 10 == 179° 42', again in parallel position. Considering the uncertainty of the angles of R, for Mr PHILLIPS gives them as 69° 12', and the same measure- ment quoted in Mr BROOKE'S Introduction to Crystallo- graphy is 69° 30', and the difficulty of obtaining a perfect- ly accurate result also from the admeasurement of the obtuse angle, it is impossible to decide whether and which member of the series the observed rhombohedron should be. 2. The rhombohedral Euchlore-mica consists of Oxide of Copper 39-00 • . 58-00. Arsenic Acid 43-00 21-00. Water 17-00 VAUCIUELIN. 21-00. CHENEVIX. It decrepitates before the blowpipe, is transformed into a black spongy scoria, and then melts into a black globule, having almost no vitreous appearance. 3. It is found in copper veins traversing killas, associat- ed with yarious ores of copper, particularly of the order Malachite, also with ochrey varieties of prismatic Iron-ore and rhombohedral Quartz. 4. Several of the copper-mines in the vicinity of Red- ruth in Cornwall, as Tingtang, Wheal Gorland, Wheal Unity, &c. have yielded varieties of the present species. 2. PRISMATIC EUCHLORE-MICA. Kupferschaum. WERN. Letztes Mineral-System. S. 19. 50. ORDER v. PRISMATIC EUCHLORE-MICA. 181 Fundamental form. Scalene four-sided pyramid of unknown dimensions. Vol. I. Fig. 9. Simple forms. P — cc ; P -f oo ; Pr + CD. Char, of Comb. Prismatic. Combinations. 1. P — oo. P+ cc. Schwatz, Tyrol. 2. P — QD. P -f- QD. pr + co. Schwatz. Cleavage, P — QD perfect. Fracture not observ- able. Surface, P -f- ce deeply streaked in a horizontal direction. The rest of the faces smooth. Lustre pearly upon P — ce, both as faces of crys- tallisation and of cleavage ; vitreous upon the , other faces. Colour pale apple-green and verdi- gris-green, inclining to sky-blue. Streak of the same colour, only paler. Translucent, general- ly only on the edges. Very sectile. Thin laminae are flexible. Hard- ness = 1-0.. .1-5. Sp. Gr. = 3-098 of a crys- tallised variety from Schwatz. Compound Varieties. Reniform and botryoidal shapes : surface drusy, composition columnar, faces of composition a little rough. OBSERVATIONS. 1. According to Mr BROOKE, the present species con- sists of hydrate of zinc and copper. 2. It occurs in beds and veins, accompanied by other ores of copper, particularly prismatic Azure-malachite, also by prismatic Zinc-bary te, rhombohedral Quartz, rhombohedral Lime-haloide, and octahedral Fluor-haloide. 3. The known localities of this species are the Bannat of 182 PHYSIOGRAPHY. CLASS II. Temeswar, Libethen in Hungary, Schwatz in the Tyrol, Saalfeld in Thuringia, and Matlock in Derbyshire. 3. fYRAMIDAL EUCHLORE-MICA. Pyramidal Uranite. JAM. Syst. Vol. II. p. 187- Pyra- midal Uran Mica. Man. p. 107. Uranite. Phosphate of Uranium. PHILL. p. 267. Uran-glimmer. WERN. Hoffm. H. B. IV. 1. S. 275. Uranoxyd. HAUSM. I. S. 327. Uranglimmer. LEONH. S. 306. Urane oxyde'. HAUY. Trait^, T. IV. p. 283. Tabl. comp. p. 114. Traitd, 2de Ed. T. IV. p. 319. PHILLIPS. Trans. Geol. Soc. Vol. III. p. 112. Fundamental form. Isosceles four-sided pyramid. P = 95° 46', 143° 9f. Vol. I. Fig. 8. AP. a = J 8-95. Simple forms. P — oo (o) ; P — 3 (c) = 118° 10', 93° 13', PHILL. ; P (P) Johanngeorgenstadt, Saxony; ^ P — 3 (e) = 120° 5', 89° 5(X; 1^1 P — 1 (/) = 101° 36', 126° 44,'; f P — 4 (d) = 137° (X, 61° 47' ; P + oo (n) ; [P + a] (m). Char, of Comb. Pyramidal. Combinations. 1. P— oo. P. Ehrenfrieders- dorf, Saxony. 2. p — oo. P-f oo. Johanngeorgenstadt, Saxony. 3. p — . oo. **L* p — 2. P. Sim. Fig. 93. Wheat Buller, Cornwall. 4. P — oo. P. [P 4- oo]. Sim. Fig. 1 1 . Tin- croft, Cornwall. Cleavage, P — GO highly perfect and easily obtained. Traces of P + oo. Fracture not observable. Surface, P — oo smooth ; the pyramids which OBDEB V. PYRAMIDAL EUCHLOEE-MICA. 183 are in a parallel position with P horizontally streaked ; [P + oo] rough. Lustre pearly upon P — oo, both as faces of crys- tallisation and of cleavage ; adamantine upon the other faces. Colour emerald-green, and grass-green, less frequently leek-green, apple- green, or siskin-green. Streak corresponding to the colour, though paler. Transparent ... trans- lucent, sometimes only on the edges. Sectile. Hardness = 2-0 ... 2-5. Sp. Gr. =3-115, a variety from Gunnislake, Cornwall. Compound Varieties. Massive: composition gra- nular, of various sizes, faces of composition rarely observable. OBSEBVATIONS. 1. According to Mr R. PHILLIPS (Ann. of PhiL New Ser. V. 57-)? the present species consists of Oxide of Uranium 60-00. Phosphoric Acid 16-00. Oxide of Copper 9-00. Silica 0-50. Water 14-50. Alone it becomes yellow before the blowpipe, and loses its transparency. Upon charcoal it intumesces a little, and melts into a black globule, with traces of crystallisation upon the surface. With borax it yields a yellowish-green bead, and produces a yellow solution in nitric acid. 2. The varieties of pyramidal Euchlore-mica occur upon veins of copper, silver, tin and iron ores, and also some- times in beds. It is accompanied by ores of copper, tin, and uranium, generally by rhombohedral Quartz, less frequent- ly by rhombohedral Emerald or prismatic Feld-spar. 3. Beautiful varieties have been obtained from Gunnis. 184 PHYSIOGRAPHY. lake mine in Cornwall, also from several mines in the neighbourhood of St Austle and Eedruth, as Tincroft, Wheal Buller, &c. In the Saxon mining districts of Jo- hanngeorgenstadt, Schneeberg, and Eubenstock, it is found in silver and iron veins ; in the same manner in the bor- dering districts of Bohemia. It occurs in veins in granite at St Symphorien near Autun, and at -St Yrieix near Limoges in France. It is likewise met with at Boden- mais in Bavaria, and near Baltimore in North America. GENUS II. COBALT-MICA. 1. PRISMATIC COBALT-MICA. Prismatic lied Cobalt. JAM. Sjst. Vol. II. p. 192. Man. p. 109. lied Cobalt. Cobalt Bloom. Arseniate of Cobalt. PHILL. p. 281. Rother Erdkobold. WEIIN. Hoffm. H. B. IV. 1. S. 201. Kobaltbliithe. HAUSM. III. S. 1124. Arseniksaures Kobalt. LEOXH. S. 304. Cobalt arseniate'. HAUY. Traite', T. IV. p. 216. Tabl. comp. p. 107. Traite', 2de Ed. T. IV. p. 232. Fundamental form. Scalene four-sided pyramid. f { 0 , . , 134° H', 82° 50'. Inclination of the axis = 9° 47', in the plane of the long diagonal. Vol. I. Fig. 41. A P. a : b : e : d = 5-8 : 11-4 : 8-1 : 1. Simple forms. ^ (/) = 1 }S° 28' ; (P + oo)3 (&) = 130° 10' ; (Pr + x)5 (*) = 94° 12' ; ^ (M) 4 ^r O ttr _j_ Q = 55° 9'; —l--^p-(o)=S905%; —fZ-l. , :(?) =27° gy; Pr + QD (T) ; Pr + x (P). ORDER v. PUISMATIC COBALT-MICA. 185 v Char of Comb. Hemi-prismatic. — ±1 = 70° 33'. Inclination of P — GO on ?r + oc = 99° 47'. Combinations. 1. — fr + GO. Pr + oo. Fig. 46. Schneeberg, Saxony. ilfLTL?. (Pr 4- QD)5. Pr + oc. Ai 2 Flatten, Bohemia. 3. *E. - *L+*. (fr + »).. f r + ao. Pr + (3D. Schneeberg. 4. ** |. (Pr+ QD)'. (?r+oo)5. ?r + oo. «c ~ Pr + QD. Fig. 172. Schneeberg. Cleavage, Pr + oo highly perfect. Traces of Pr + op 4 pr — _ g and — I __ . Fracture not observable. Sur- face, Pr + oo streaked parallel to the edges of combination with Pr + QD, the rest of the faces streaked parallel to those with Pr -j- oo. Lustre pearly upon Pr -f oo, particularly if pro- duced by cleavage. The rest of the faces pos- sess adamantine lustre inclining to vitreous. Colour, crimson-red, cochineal-red, peachblossom- red, sometimes pearl -grey or greenish-grey. The red tints of the former, by transmitted light, in- cline much more to blue, if seen in a direction perpendicular to Pr -f- oc, than in that perpen- dicular to Pr + oo. Streak corresponding to 186 PHYSIOGRAPHY. CLASS II. the colour, though a little paler. If the mineral be crushed into powder in a dry state, this powder possesses a deep lavender-blue tinge, which is not the case if the powder be comminuted in wa- ter. Transparent... translucent on the edges. Crystals are least transparent in a direction per- pendicular to Pr -f- oo. Sectile ; thin lamina? are flexible parallel to the in- 4 jSr Q tersection of Pr -f GO with — I Hard- 2 ness = 1-5 ... 2-0, the lowest degrees upon Pr + QD. Sp. Gr. = 2-948, a red crystallised variety from Schneeberg.* Compound Varieties. Implanted globular and reniform shapes ; surface drusy ; composition more or less perfectly columnar, of various sizes of in- dividuals, faces of composition either smooth or rough. Massive, composition columnar, often stellularly divergent, and aggregated in a second granular composition, faces of composition rough. Sometimes in a state of powder as a coating upon other minerals. OBSERVATIONS. 1. The species Red Cobalt is generally divided into two sub-species, Colalt-Bloom and Cobalt-Crust. The for- * The Privy Counsellor, Baron VON HERDER, kindly com- municated to me several beautiful varieties of the species, to which the preceding general description more particularly refers. M. ORDER v. PRISMATIC COBALT-MICA. 187 mer of these contains the more perfectly formed varieties, which appear as crystals, as micaceous scales, aggregated into globular masses, or crystalline coats, as long as the in- dividuals are still recognisable. When they cease to be observable, the second sub-species is formed, which consists of a peachblossom-red powder, either coating pther mine- rals, or mixed up with, and imparting to them, an extrane- ous colour. The black, brown, and yellow Cobalt-Ochre do not stand in any natural-historical relation with the pre- sent species. 2. The chemical composition has been found by BUCHOLZ to be, Oxide of Cobalt 39-00. Arsenic Acid 37-00. Water 22-00. Its chemical formula is Co3 As2 +12 Aq, and the correspond- ing ratio of its ingredients, 39-95 oxide of cobalt, 40-90 ar- senic acid, and 19-J5 water. Alone before the blowpipe it assumes a darker colour. Upon charcoal it emits copious arsenical fumes, and melts in the inner flame into a bead of arseniuret of cobalt. With borax and other fluxes it yields a fine blue coloured glass. 3. It occurs in veins traversing rocks of various ages, and also in beds. It is accompanied by various minerals, as Nickel- and Cobalt-pyrites, octahedral Bismuth, several species of the orders Malachite and Glance, also by ochrey varieties of prismatic Iron-ore, and particularly by rhombo- hedral Quartz, prismatic Hal-baryte, and rhombohedral Lime-haloide. 4. The principal localities of this species are, Schneeberg and Annaberg in Saxony, and Flatten in Bohemia, where it occurs in veins in primitive rocks ; Saalfeld in Thuringia, Riegelsdorf and Bieber in Hessia, where it is found in veins in secondary mountains. It is besides found in Wiirtemberg, in the district of Siegen in Prussia, in the Tyrol, in Norway and in Sweden. It is met with also in several places in England and in Scotland. 188 PHYSIOGRAPHY. CLASS II. 5. Where it occurs in sufficient quantities, it is used as a valuable mineral in the process of obtaining smalt GENUS III. IRON-MICA. 1. PRISMATIC IRON-MICA. Prismatic Blue Iron. JAM. Syst. Vol. II. p. 209. Man. p. 115. Phosphate of Iron. Vivianite. PHILL. p. 238. Blaue-Eisenerde. Krystallisirte Blaueisenerde. Vivi- anit. WERN. Hoffm. H. B. III. 2. S. 302., IV. 2. S. 144. Min. Syst. S. 9. 41. Eisenblau. HAUSM. III. S. 1075. Phosphorsaures Eisen. LEONH. S. 357. Fer phosphate'. HAUY. Tabl. comp. p. 99. Traite", 2de Ed. T. IV. p. 126. Fundamental form. Scalene four-sided pyramid. P = :! *' , 134° 31', 82° 48'. Inclination of the axis = 10° 53' in the plane of the long diagonal. Vol. I. Fig. 41. AP. a : b : c ; d = 5-2 : 10-2 : 7-3 : 1. Simple forms. ?. = 119° 4' ; (Pr -f oo)3 — 111° 2 6'; (Pr-f )8 = 154° 14'; ^ = 54° 13'; ?r + cc ; Pr -f- OD. p Char, of Comb. Hemi-prismatic. — _ = 71° 34'. Inclination of P — oo to Pr -f- OD = 100° 53'. Combinations. 1. —. Pr + CD. Pr + oo. Sim. X Fig. 46. Bodenmais, Bavaria. 2. S* ?. (?r -f ex.)5. Pr + GD. Pr -f- OD. ORDER v. PRISMATIC IRON-MICA. 189 Sim. Fig. 72., only having the edge of the py- ramid replaced. St Austle, Cornwall. 3. ^. (Pr 4- «)5. (? + oo) 6. ?r + oo. % Pr + oo. Cornwall. Cleavage. Pr -f- oo highly perfect. Traces of ?r + OD and — iZl^ = 90° 55'. Fracture 2 not observable. Surface, Pr + QD smooth ; the rest of the faces streaked parallel to the edges of combination with Pr + GO. Lustre pearly, almost metallic upon Pr + CD. The rest of the faces possess vitreous lustre. Colour pale blackish-green ... indigo-blue. It is green in the direction of the axis and in the plane of inclination, also perpendicular to the latter, but of a pure blue colour nearly in the directions of (Pr + oc)3, and perpendicular upon Pr. The united effect of both produces the common dirty indigo-blue colour. Streak blueish-white, very soon changed into indigo- blue. The powder produced by crushing the mineral in a dry state is liver-brown. Trans- parent ... translucent; least transparent in a di- rection perpendicular upon Pr + oo. Sectile. Thin lamina? are perfectly flexible par- allel to the intersection of Pr -f oo with — ? pr -7L2. Hardness = 1-5 ... 2-0, the *v 190 PHYSIOGRAPHY. CLASS II. lowest degrees upon Pr -|- oo, Sp. Gr. = 2-661 , a crystal from Cornwall. Compound Varieties. Small reniform and glo- bular shapes, and imbedded nodules ; also super- ficial coatings of dusty particles. Composition im- palpable, earthy or easily reduced to powder. OBSERVATIONS. 1. The forms of the present species possess a remarkable analogy with those of other hemi-prismatic species, par- ticularly of prismatoidal Gypsum-haloide and prismatic Cobalt-mica. The cornish varieties in transparent crystals have been distinguished from the rest under the name of Vivianite. The rest of the crystallised varieties under the denomina- tion of the Prismatic Blue Iron, were again separated from the compact and earthy varieties, or the Earthy Blue Iron. These distinctions, however, seem to foave been introduced only from the succession of the discovery in regard to the varieties which they comprehend, and not from any scien- tific or classificatory principle. 2. In two varieties, a friable one analysed by KLAPROTH, and a crystallised one from Bodenmais in Bavaria by Vo- GEL, the following chemical constituents have been dis- covered : Protoxide of Iron 47'50 41-00. Phosphoric Acid 32-00 26-40. Water 20-00 31-00. Its chemical formula, derived from the second analysis, is Fe2 P + 12 Aq, which corresponds to 43*88 protoxide of iron, 22-28 phosphoric acid, and 33-84 water. It decrepi- tates before the blowpipe, but melts, if first reduced to powder, into a dark brown or black scoria, which moves the magnetic needle. It is soluble in dilute sulphuric and ftitrie acids. The friable varieties are found white in their ORDER V. RHOMBOHEDRAL GRAPHITE-MICA. 101 original repositories, but like the white powder of the crystals, they soon assume a blue tinge, on being exposed to the air. 3. The varieties of the present species occur in different kinds of natural repositories. Some of them are found crystallised, particularly accompanied by hexahedral Iron- pyrites in copper and tin veins ; others in very narrow veins traversing greywacke, partly with hexahedral Gold, and other species, which accompany the latter; still others, probably in beds, along with rhombohedral Iron-pyrites, octahedral Iron-ore, and some at last are disseminated in basalt, and other trap rocks. The compound, friable varie- ties are imbedded in clay, and in the depositions of bog iron-ore, which indicate a more recent formation of it. 4. The first varieties exhibited in the cabinets of mi- nerals were those from Vorospatak in Transylvania, where they are found in the gold mines, and have been consider- ed as blue gypsum. The Vivianite occurs near St Agnes in Cornwall, the Prismatic Blue Iron at Bodenmais in Bavaria, in several districts of France, in Isle de France, &c. partly imbedded in mountain rocks. The Earthy Blue Iron is found in the Gail valley in Carinthia, at Ligist and other places in Stiria, at Eckartsberge in Thuringia, in Wurtemberg and Baden, in Lusatia, and other countries. It has been discovered in several peat mosses in the Shet- land Islands, also at Ballagh in the Isle of Man, where it is associated with elks' horns, in river mud near Liver- pool, &c. GENUS IV. GRAPHITE-MICA. 1. RHOMBOHEDRAL GRAPHITE-MICA. Rhomboidal Graphite. JAM. Syst. Vol. II. p. 216. Man. p. 117. Plumbago. Graphite. Black Lead. PHILL, > 364. Graphit. WERN. Hoffm. H. B. III. 1. S. 309. Graphit. HAUSM. I. S. 67. Graphit. LEONH. S. 334. Fer carbure'. HAUY. Traite', T. IV. p. 98. Graphite. Tabl. comp. p. 70. Fer carbure ou Gra* phite. Traite', 2de Ed. T. IV. p. JJa. 192 PHYSIOGRAPHY. CLASS ir. Fundamental form. Rhombohedron of unknown dimensions. Vol. I. Fig. 7. Simple forms II — QD; R -f x ; P ; • P + o> ; in various combinations, as : R — oo. P. P -f GO, simi- lar to Fig. 112, &c. but possessing a tabular aspect. Character of combinations di-rhombo- hedral. Cleavage, R — GO highly perfect. Fracture un- even, scarcely observable. Surface, R — QD and P generally smooth or faintly striated paral- lel to their edges of combination, the rest of the faces rough. Lustre metallic. The highest degrees of lustre are found upon R — oo, both as faces of crystallisa- tion and of cleavage. Colour iron-black, dark steel-grey. Streak black, shining. Opake. Sectile. Thin laminae are highly flexible. Hard- ness = 1-0.. .20. Sp. Gr. — 2-0891, HAUY. Compound Varieties. Massive : composition gra- nular, the individuals flat and scaly, of various sizes, frequently impalpable. Of the latter, the frac- ture is conchoidal or even. OBSERVATIONS. 1. Tha division of the species Graphite into Scaly and Compact Graphite, depends upon the size of the grain in the compositions, the former comprehending those which are still discernible, while in the latter they are withdrawn from observation. The simple varieties have been either united with scaly Graphite, or they have been considered as a particular sub-species (Hoffm. H.B. IV. 2. S. 171.). 2. The rhombohedral Graphite-mica consists of ORDER r. PRISMATIC TALC-MICA. 1Q3 Carbon 81-00 92-00 9C-00. Iron 10-00 8-00 4-00. Oxygen 9-00. SCHEELE. 0-00. VAUQ. 0-00. SAUSS. In a high degree of heat it is combustible, and leaves a residue of oxide of iron. It is infusible alone, and with additions. 3. The varieties of this species are found in beds, or form beds by themselves, in slaty and ancient trap-rocks. They seem often to replace the different species of Talc-mica in mixed rocks, particularly in gneiss, if con- taining a great proportion of Feld-spar. In the beds of rhombohedral Lime-baloide, the rhombohedral Graphite- mica occurs in single crystals, or in imbedded massive varie- ties. It is likewise met with in the coal formation. 4. One of the most remarkable repositories of rhombo- hedral Graphite-mica is at Borrowdale in Cumberland, a bed of trap very much interrupted, and alternating with clay-slate. In the neighbourhood of Hafnerzell, Gries- bach, &c. in Passau, in Austria, Moravia, and other coun- tries, it forms a constituent part of gneiss ; in Lower Stiria it is imbedded in granular limestone. It occurs crystallis- ed in Greenland, in the parish of Pargas in Finland, and different varieties are known from the Tyrol, Salzburg, Piedmont, France, Spain, Norway, and America. In the coal formation it is found at Cumnock in Ayrshire. 5. The chief employment of this mineral is in manufac- turing pencils and crucibles, the latter particularly for the purposes of the mint. It is also used for giving a gloss to iron stoves and railings, and for diminishing the friction in machines. GEXUS V. TALC-MICA. 1. PAISMATIC TALC-MICA. Rhomboidal Mica (in part). JAM. Syst. Vol. II. p. 221. Prismatic Talc-Mica (in part). Man. p. 119. Talc. Green Earth. Chlorite. PHILL p. lie. liy. 120. YOL II. N 194 PHYSIOGRAPHY. CLASS n. Tqpfstein. Grunerde. Chlorit. Talk. WEHN-. HofFm. H. B. II. 2. S. 131. 134. 195. 267. Chlorit. Topf- stein. Talk. HAUSM. II. S. 490. 496. 497. Chlorit. Talk. Topfstein. LEONH. S. 4C5. 466. 467. Talc (in part). HAT: Y. Traite, T. III. p. 252. Tabl. comp. p. 56. Traite', 2de Ed. T. II. p. 489. Fundamental form. Scalene four-sided pyramid of unknown dimensions. Vol. I. Fig. 9. Simple forms. P — oo ; P -f- oo = 120° (nearly) ; Pr + CD ; Pr -|- oo ; in various combinations presenting hexagonal, rhomboidal, and rectan- gular plates. Cleavage, P — oo, commonly highly perfect. Frac- ture not observable. Surface P — oo smooth. The faces of the other forms streaked parallel to the edges of combination with P — oo. Lustre pearly upon P — oo, both as faces of crys- tallisation and of cleavage. The faces of the other forms possess vitreous lustre, inclining to adamantine, generally low degrees. Colour, various shades of green, as blackish-green, leek-green, celandine-green, and apple-green, passing into greenish-grey, greenish-white, and greyish-white. Streak corresponding to the co- lour, green . . . white. Semi-transparent . . . trans- lucent. Different colours in different directions. Some individuals are of a bright green colour if viewed in a direction perpendicular to the la- minae, while parallel to them they exhibit in other directions a fine brown tinge. In the lat- ter direction they are much more transparent than in the former. ORDER v. PRISMATIC TALC-MICA. 1Q5 Sectile, in a high degree. Thin laminae are easily flexible. Hardness = 1-0... 1-5. Sp. Gr. =2-713 a dark-green variety, compound of large indi- viduals. Compound Varieties. Imperfect globules and stellular groupes : composition imperfect columnar. Sometimes several crystals are engaged with each other, so as to produce conical and cylindrical ag- gregations. Massive : composition granular of va- rious sizes of individuals, often impalpable ; some- times imperfect columnar. The individuals are sometimes strongly coherent with each other, or flat, so as to give rise to an imperfect slaty structure. Often earthy, without connexion of its particles. OBSERVATIONS. 1. The difference among the species and sub-species, comprehended within prismatic Talc-mica, depends upon various properties at the same time, both of the individuals themselves and of their compositions, and it is not there* fore without many difficulties. The varieties of dark- green (leek-green, celandine-green, &c.) colours, inclining to brown, constitute the Chlorite, subdivided into foliated and common, slaty and earthy Chlorite. The first of these contains the crystallised varieties, and such compound ones as consist of easily separable individuals, not presenting a slaty structure. The second contains those granularly compound varieties, in which the individuals can scarcely be traced, or in which they are not observable at all. Chlorite-slate, or slaty Chlorite, refers to such compound varieties as have a slaty texture, and earthy Chlorite to such as are but loosely coherent, or already in a state of loose scaly particles; and it is distinguished from foliated Chlo- 196 PHYSIOGRAPHY. CLASS n. rite only by the smallness of its grain. Immediately with those varieties of Chlorite whose composition is impalpable, the Green Earth is connected, from which, however, we must except what has been termed crystallised Green- earth, and which consists of decomposed crystals of para- tomous Augite-spar. The species Talc comprehends the varieties of generally pale green, particularly apple-green, grey and white varieties, and is divided into common, earthy, and indurated Talc. Simple varieties are common Talc ; also such compound ones in which cleavage is transformed into slaty structure, the latter being generally very per- fect ; or such as consist of columnar particles of composi- tion ; earthy Talc, or Nacrite, consists of loose particles, or such as are but slightly cohering ; and indurated Talc refers to imperfect and coarse slaty varieties, in which this kind of structure is more the consequence of composition than of imperfect cleavage. If this structure be sufficiently im- perfect to become coarse and indistinctly granular, Pot-stone or Lapis ollaris is formed, which, possessing the united pro- perties of softness and tenacity, may be easily turned into vessels ;* and it is perhaps only for that reason that it used to be distinguished as a particular species. It must be re- marked, however, that several of the most important natu- ral-historical properties of the substances at present com- prised within the species of prismatic Talc-mica, are too little known to admit of an exact comparison, so that they may possibly require in future to be divided into several species. 2. Three varieties of the present species, foliated Talc analysed by VAUQUELIN, slaty Chlorite analysed by GRU- NER, and Green Earth analysed also by VAUQUELIN, have yielded : * I have been informed by Captain STEWART, that the translucent white variety of common Talc from Almorah, in the Himalayan mountains, is employed for the same pur- poses. H. IDEBT. PRISMATIC TALC-MICA. 197 Silica 62-00 29-50 52-00. Magnesia 27'00 21-39 6-00. Oxide of Iron 3-50 23-39 23-00. Alumina 1-50 15-62 7'00. Water 6-00 7 '38 4-00. Potash 0-00 0-00 7'50. Lime 000 1-50 0-00. These analyses, as well as those of several other varieties of the species, shew that our information also in respect to its chemical constituents is still very defective. Before the blowpipe some of them lose their colour, and are difficultly fusible, others are changed into a black scoria, still others are infusible. In these phenomena also there is so little agreement between the varieties employed, that we are forced to draw the conclusion, either that the varieties were not pure enough, or not simple ones, which they al- ways should be if we wish to arrive at a correct result, or that they belonged to different species. 3. Common Talc, indurated Talc, Potstone and slaty Chlorite, constitute themselves beds in primitive mountains. The latter frequently contains imbedded crystals of octa- hedral Iron-ore ; some of the former contain rhombohedral Fluor-haloide, several species of Lime-haloide, of Augite- spar, &c. Common Chlorite in particular is found in beds in primitive rocks, consisting chiefly of ores of iron, rhombohe- dral Lime-haloide, and several species of the genus Augite- spar. Other varieties, and among these the small scaly crys- tals of foliated Chlorite and earthy Chlorite, occur in veins of various descriptions, and in the crystal caves of the Alps. Green-earth, and sometimes also foliated Chlorite, occur in amygdaloidal rocks, where they are found either lining the vesicular cavities, or as imbedded nodules in the body of the rock itself. Earthy Talc or Nacrite, of whose natural his- torical properties but little is known, has been found in lead veins. 4. Those varieties which by themselves form mountain masses, are met with in the primitive districts of several countries, as in the Tyrol, in Salzburg, Switzerland, Swe- 198 PHYSIOGRAPHY. CLASS n. den, Norway, Corsica, &c., in the Grampians in Scotland, in Unst, one of the Shetland isles. Upon beds and veins with metallic ores and Pyrites they are found in consider, able quantities in Cornwall, where they are known by the name of Peach, also in Saxony, Salzburg, Sweden, &c. The crystallised varieties occur in veins, frequently in mount St Gothard in Switzerland, also in Salzburg, Sweden, and other countries. The chief localities of Green- earth are the Monte Baldo near Verona, Iceland, the Faroe islands, Tyrol, Hungary and Transylvania, and various places in Great Britain and Ireland. 5. Some of the varieties occurring in beds in large masses, are used as fire-stones in iron furnaces. In Switzerland potstone is turned into culinary and other vessels, and worked into plates for the construction of stoves. Green, earth is used, both raw as a green colour, and burnt as a reddish -brown colour, for painting houses, &c. The Vene- tian Talc, a variety of common Talc of a greenish-white colour, formerly used as a medicine, seems to be no longer 2. EHOMBOHEDRAL TALC-MICA. Rhomboidal Mica (in part). JAM. Syst. Vol. II. p. 221. Khomboidal Talc-Mica, Man. p. 127- Mica. PHILL. p. 106. Glimmer. WERN. Hoffm. H. B. II. 2. S. 115. Glimmer. HAUSM. IT S. 487. Glim- mer. LEONH. S. 4C1. Mica. HAUY. Trait^, T. III. p. 208. Tabl. comp. p. 53. Traitd, 2de Ed. T. III. p. 111. Fundamental form. Rhombohedron of unknown dimensions. Vol. I. Fig. 7. Simple forms. R _ (P) ; R -f- oo ; P (*, *') ; P + oo (My r). Various combinations of these forms, whose character seems to be di-rhombohedral, as l.R — or. P-f-oo; 2. R — GD. P. P + oc; 3. R. — x. P. R + QD. P + OD,&C. OBDER v. RHOMBOHEDBAL TALC-MICA. 199 Cleavage, R — oo, highly perfect, and easily ob- tained, passing in less perfectly formed varieties into slaty structure. Traces of P + oo. Frac- ture scarcely observable, uneven. Surface P and P -f oo horizontally streaked, the other faces, particularly R — oo, smooth. Lustre pearly, often inclining to metallic upon R — QD ; the other faces, if they are smooth enough, present a kind of lustre between vitre- ous and adamantine. Colour various shades of grey, generally passing into green, brown, and black, also into white and red (particularly peachblossom-red). Superficial tinges of pinch- beck-brown. Streak white, grey. Transparent, imperfectly... translucent on the edges. It is less transparent in the direction of the axis than perpendicular to it. There is also a dif- ference of colours observable in these directions, for instance, oil -green in the first, and liver- brown in all the others. Sectile. Thin laminae are elastic. Hardness = 2-0 ...2-5. The acute edges of the laminae, however, will sometimes scratch glass. Sp. Gr. = 2-949, a greenish-black variety in large individuals. Compound Varieties. Globular forms, both imbedded and implanted : surface of the latter rough ; composition columnar, sometimes joining in a second curved lamellar composition. Massive: composition granular of various sizes of individuals ; or also imperfect columnar, faces of composition irregularly streaked and rough. 200 PHYSIOGRAPHY. CLASS 11. OBSERVATIONS. 1. The substances hitherto comprised under the name of Mica, do not all belong to the [species of rhombohedral Talc-mica ; but it would be impossible, from the present im- perfect state of our information, to draw clear lines of se- paration between the various species designated by that name. Although in several of them the system of crystal- lisation be known, yet we are not acquainted with the re- spective series of crystallisation, that is to say, with the angles of the fundamental rhombohedrons or scalene four- sided pyramids ; and the distinctive characters which then remain are not in general sufficient to give security and evidence to the determination of the species. The optical researches, however, of Dr BREWSTER and M. BioT,have shewn that the various kinds of Mica differ considerably in their action upon light, some of them possessing only one axis of double refraction, and shewing one system of co- loured rings, while others possess two axes, and shew there- fore two systems of coloured rings. Among the first again, some possess a positive optical axis like rhombohedral Quartz, though the greater part of them exhibit a negative one, like rhombohedral Lime-haloide. The resultant axes, or those of no polarisation in the other, are inclined to each other at various angles, and, besides, are situated in planes perpendicular to the laminae, which in some of them pass through the long diagonal, in others through the short diagonal of a rhombic prism of 120° and 60°, supposed to result from the enlargement of four of the lateral faces of the six-sided laminae. Count BOURNON assumes an oblique rhombic prism for the primitive form of Mica. According to Mr SORET, who likewise supposes the primi- tive form of certain varieties of mica to be an oblique prism, the plane of the resultant axes passes in these through the short diagonal of the base, and this takes place in several micas from Sweden and Siberia. In others, where the primitive form is a right prism, the plane of the resultant axes passes through the long diagonal of the base, ORDER 11HOMBOHEDRAL TALC-MICA. and this is the case in the micas from St Gothard and from Altenberg in Saxony. Several crystallised varieties from Vesuvius, of a pale green colour, and others from various localities, presenting green, brown, and black colours, pos- sess one axis of double refraction. The forms of the mi- nerals called Mica thus appear to belong to three different systems of crystallisation ; they are sufficient to shew how much there is yet to be done in examining their varieties. 2. Not less at variance, and partly in opposition with each other, we find the results of chemical analyses of the different kinds of mica, as comparatively instituted and published by KLAPHOTH, ROSE, and PESCHIER. indents. jg^ From Siberia. From St Gothard. From Kiinito. Alumina 20-00 34-25 22-00 o-oo 36-80 Silica 47-00 48-00 40-25 19-50 46-36 Oxide of Iron 15-50 4-50 8-75 26-50 4-53 Ox. of Titanium 0-00 000 13-00 25-40 0-00 Ox. of Manganese 1-75 a trace 2-00 25-25 0-00 Magnesia 000 0-50 o-oo o-oo a trace L,ime 0-00 o-oo 1-75 0-00 0-00 Potash 14-50 8-75 7-25 o-oo 9-22 Fluoric acid 1 and water ) o-oo o-oo 3-24 o-oo 1-81 KLAFR. KLAPR. PESCH. PESCH. ROSE. From a comparison of these analyses, it appears that there exist differences among the varieties of mica, which, how- ever, it is impossible to reduce to fixed points, so long as we are in want of an accurate natural-historical deter, inination of the species. This determination must flow from principles of Natural History, and can the less depend upon chemical relations, as the very object of a great part of the present researches of chemistry consists in examining the nature of the composition in those bodies which form species in Natural History. Before the blow- pipe, several varieties first lose their transparency, and then melt into a scoria, white or coloured, or even black. Others are infusible, and they shew in general as much difference in this respect as in their composition. PHYSIOGRAPHY. CLASS n. 3. Mica forms one of the constituent parts of various rocks, as granite, gneiss, mica-slate, and of several varie- ties of porphyry. They form sometimes more or less considerable nodules and concretions in these rocks, and then contain imbedded crystals of prismatic Topaz, rhom- bohedral Tourmaline, and other species. As single crystals, they appear not unfrequently imbedded in granular lime- stone, in basalt and wacke, in implanted crystals upon the specimens ejected by Mount Vesuvius. Several varieties of mica accompany in metalliferous beds, the ores of tin and scheelium, and they occur likewise in ancient veins, which consist of those species which are contained in the rocks which they traverse. 4. Remarkable varieties of Mica are found in Siberia, particularly cleavable ones in large individuals, crystallised ones at .Zinnwald in Saxony, possessing two axes of double refraction. It is also found in the Hb'rlberg in Bavaria, in imbedded globules in Moravia, in Mount St Gothard in Switzerland, at Finbo in Sweden, in Pargas in Finland, here with curved faces of cleavage ; at "Wiesenthal in Sax- ony, and Joachimsthal in Bohemia, imbedded in basalt and wacke, &c. At Mount Vesuvius, crystals of Mica with one axis, often of considerable size and transparency, occur in the drusy cavities of the ejected specimens. It occurs besides in great variety in many other countries. 5. Perfectly cleavable varieties, which are transparent at least if reduced to a considerable tenuity, are used in Si- beria, in Mexico and Peru, instead of window glass ; and from the first of these countries, they have on that account received the name of Muscovy glass. In Siberia, the ex- traction of the large crystalline masses imbedded in granite, forms an object of mining. It is sometimes used for vari- ous optical purposes, and enters the composition of the artificial avanturine. 6. Lepidolite^ a substance included by some authors within the species of mica, possesses two axes of double refraction, and its forms therefore are likely to belong to ORDEB V. EHOMBOHEDBAL TALC-MICA. the prismatic system, though they have not yet been ob- served. It occurs in granular compositions of a peachblos- som-red colour, sometimes passing into several pale shades of green. The specific gravity of Lepidolite is constantly lower than that of the rest of the varieties of mica, having been found in a very pure variety = 2*832. Its chemical constituents are, according to WENZ, Alumina 33-61. Silica 49-06. Oxide of Manganese 1'40. Magnesia 0-41. Lithia 3-60. Potash 4-18. Fluoric Acid 3-45. Water 4-18. and a trace of oxide of iron. Before the blowpipe upon charcoal, it intumesces, and fuses very easily into a trans- parent globule. It has been found near Rozena in Mora- via, and at Uto in Sweden, in primitive rocks. It is cut into snuff-boxes and various ornaments. 7. Clay-slate is in a very close connexion with the differ- ent substances comprised within the name of Mica, and uninterrupted transitions may be found from those posses- sing low degrees of perfection in their cleavage into the varieties of clay-slate. This substance, besides, cannot be considered as a particular species, being generally not only compound, but even mixed. Its varieties are in immediate connection with mica-slate, which is again united to granite by means of gneiss. The proportion of mica, which forms one of the constituents of the latter, increases ; and while the others diminish in quantity and size, so as to be not observable at all in clay-slate, it imparts to this rock most of the properties by which it is characterized. This is the result of immediate observation, and hence may also be explained the varieties met with in clay-slate, and which have given occasion for designating some of them by parti- cular names. Most of the other slaty rocks are more or less allied to clay-slate. 204 PHYSIOGRAPHY. CLASS H. Also the results of chemical analysis correspond with this mode of viewing the subject. M. D'AUBUISSON has found one of its varieties to consist of Alumina 23-50. Silica 48-60. Oxide of Iron 11-30. Oxide of Manganese 0-50. Magnesia 1-60. Potash 4-70. Water 7'60. Carbon 0-30. Sulphur 0-10. Clay-slate melts into a scoria. It forms rocks, and is asso- ciated and alternates with various other rocks possessing a slaty structure. It occurs in primitive and transition mountains. Sometimes it includes crystals of Chiastolite, more frequently it contains crystals of hexahedral Iron- pyrites. It is spread over many countries as a rock, giving in many places occasion to important mining proceedings. It is used also as a roofing slate, for manufacturing slates for drawing and writing, and some varieties also as whet- stones. It is employed as a flux in melting ores of iron ; but most of its varieties are useless for purposes of build- ing or paving. i GENUS VI. PEARL-MICA, 1. RHOMBOHEDRAL PEARL-MICA. Rhomboidal Pearl Mica. JAM. Man. p. 129. Margarita (of Fuchs). PHILL. p. 208. Perlglimmer. LEONH. S. 655. Fundamental form. Rhombohedron of unknown dimensions. Vol. I. Fig. 7. Simple forms R — "•> f°r the rest low degrees of an imperfect vitreous lustre. Colour dirty shades of leek-green and blackish- green, also liver-brown, hair-brown and clove- brown, greenish- and ash-grey. They are heightened by a metalloidal appearance upon j>r _|_ op, and often incline to pinchbeck-brown. Streak corresponding to the colour, yellowish- or greyish- white. Translucent, sometimes only on the edges. Rather sectile. Hardness = 4-0.. .50. Sp. Gr, = $-251, a brown variety from Bayreuth. Compound Varieties. Massive : composition granular, of various sizes of individuals, strongly connected. OBSERVATIONS. 1. The bem'-pr!smatic Schiller-spar consist?, according to KkAPBOTH, Of ORDER vi. PRISM ATOI DAL SCHILLER-SPAR. 209 Silica 60-00. Magnesia 27-50. Oxide of Iron 10-50. Water 0-50. By the action of fire it assumes a lighter colour, and loses its water, but is by itself infusible before the blowpipe. 2. The varieties of this species occur in imbedded crys- talline particles, either simple or compound, in serpentine and greenstone rocks. There are even beds included in the serpentine formation, which consist almost entirely of hemi-prismatic Schiller-spar, and are mixed with compound varieties of hemi-prismatic Augite-spar. It is often associ- ated with those species which are commonly found in ser- pentine rocks. 3. It is found in considerable quantities, in and near the Gulsen mountain, in the vicinity of Kraubat in Stiria, where it forms those beds in serpentine, of considerable ex- tent, alluded to above. It occurs near Hof in Bayreuth, at the Baste in the Hartz in green-stone, in the Bacher mountain in Lower Stiria, and the Lizard district of Corn- wall in serpentine, and under similar circumstances in va- rious other countries. 3. PRISMATOIDAL SCHILLER-SPAR. Hypersthene or Labrador Schiller-Spar. JAM. Syst. VoL II. p. 178. Prismatoidal Schiller-spar or Hy- persthene. Man. p. 132. Hypersthene. PHILL. p. 70. Paulit. WEEN. Hoffm. H. B. II. 2. S. 143. Hy. persthen. HAIJSM. II. S. 718. Hypersthen. LEONH. S. 519. Diallage metalloide. HAUY. Traite', T. III. p. 127. Hypersthene. Tabl. comp. p. 44. Trait** 2de Ed. T. II. p. 447. Fundamental form. Scalene four-sided pyramid of unknown dimensions. The simple forms and the character of the combinations are also un- known. VOL. II. O 210 PHYSIOGRAPHY. CLASS II. Cleavage, parallel to the sides of a four-sided prism of about 93°, more perfectly parallel to the short diagonal of that prism, traces parallel to the long diagonal. Fracture uneven. Lustre eminent metallic-pearly upon the single per- fect faces of cleavage ; in other directions more or less distinctly vitreous. Colour greyish- or greenish-black ; several varieties almost copper- red upon the perfect face of cleavage. Streak greenish-grey. Opake, in some varieties slightly translucent on the edges. Brittle. Hardness = 6-0. Sp. Gr. = 3-389, the American variety. Compound Varieties. Massive : composition granular, sometimes of considerable size of indivi- duals ; faces of composition uneven and rough. OBSERVATIONS. 1. According to KLAPROTH, the prismatoidal Schiller- spar consists of Silica 54-25. Magnesia 14-00. Alumina 2-25. Lime 1-50. Oxide of Iron 24-50. Water 1-00. and a trace of oxide of manganese. If heated alone, it is little altered in appearance, but melts upon charcoal into a greenish-grey opake globule, easily soluble in borax. 2. The varieties of the present species occur engaged in a mixture of Labradore, a species of the genus Feld- spar, of hemi-prismatic and paratomous Augite-spar. The rock often contains octahedral Iron-ore, and seems to be ORDER VI. PRISMATIC SCHILLER-SPAR. analogous to syenite or greenstone. They are also said to have been found in a slaty rock with dodecahedral Garnet, and in serpentine along with Saussurite. 3. It has first been brought from the coast of Labrador in North America, and in reference to this locality, it was named Labradore hornblende ; which name, however, was afterwards exchanged for Paulite, from the island of St Paul. It has been mentioned from Cornwall, where it is said to occur in serpentine, and in primitive slate in Greenland. The variety from the latter place with a blue opalescence parallel to the short diagonal of the prism, which has been considered as a variety of the present spe- cies, presents two faces of cleavage inclined at an angle of about 124|°, and must be referred to the species of hemi- prismatic Augite-spar, as has first been observed by Mr BROOKE. 5. PRISMATIC SCHILLER-SPAR. Anthophyllite. JAM. Syst. Vol. II. p. 181. Prismatic Schiller-spar or Anthophyllite. Man. p. 133. Antho- phyllite. PHILL. p. 69. Strahliger Anthophyllit. WERN. Hoffm. H. B. I. S. 673. Anthophyllit. HAUSM. II. S. 720. Anthophyllit. LEONH. S. 432. Anthophyllite. HAUT. Tabl. comp. p. 58. Anthophyl- lite. Traite', 2de Ed. T. II. p. 600. Fundamental form. Scalene four-sided pyramid of unknown dimensions ; so are also simple forms and the character of combinations. Cleavage, parallel to the sides of a four-sided prism of about 124|° and both its diagonals, the cleavage parallel to the long diagonal being more distinct, and easily obtained. Fracture uneven. Surface streaked parallel to the axis. Lustre pearly, inclining to metallic, particularly upon the perfect face of cleavage, Colour be- PHYSIOGRAPHY. CLASS II. tween yellowish-grey and clove-brown. Streak white. Translucent, sometimes only on the edges. Brittle. Hardness = 5-0 ... 5-5. Sp. Gr. = 3-129. BLODE. Compound Varieties. Massive : composition co- lumnar, straight, sometimes divergent, and rather broad ; faces of composition irregularly streaked. They are often aggregated in a second composition, which is angulo-granular and wedge-shaped. OBSERVATIONS. 1. An analysis by JOHN states the component parts of the present species to be Silica 56-00. Alumina 13-30. Magnesia 14-00. Lime 3-33. Oxide of Iron 6-00. Oxide of Manganese 3-00. Water 1-43. Alone it is not altered, and infusible before the blow-pipe. It is dissolved, though with difficulty, by borax, and yields a glass coloured by iron. 2. The prismatic Schiller-spar occurs in beds of mica- slate, accompanied by rhombohedral Quartz, dodecahedral Garnet, several varieties of Talc-mica, of hemi-prismatie Augite-spar, prismatic Feld-spar, of Cobalt- and Copper- pyrites, &c. Thus it has been found at Kongsberg, and the cobalt mines of Modum in Norway. With hemi-pris- matic Augite-spar it has been discovered in Greenland. 3. Although, according to the present state of our infor- mation, and agreeably to the principles of Natural History, the determination of the present genus seems to be unex- ceptionable; yet much is still necessary for a perfect deter- OilDEH vi. PRISMATIC DISTHENE-SPAR. niination of the species which it comprehends. The opi- nions of mineralogists have been much at variance in regard to these substances ; but generally they have placed them near each other in their systems, on account of their close resemblance, upon which depends the deter- mination of the genus. A more accurate examination of their forms will remove in future every doubt on the determination of the species, and then only will it be possible to adapt the systematic nomenclature to the geometrical properties of the species, which always must correspond to the state of our information. Mr HAI- DIJTGER has shewn, (Trans, of the Royal Soc. of Edinb. VoL X. p. 127.) that one of the formerly supposed spe- cies of the present genus, the Green Diallage of HAUY, contains nothing but varieties of two other species, the hemi-prismatic and paratomous Augite-spar, either pure or variously blended with each other. An exact com- parison of several varieties of the remaining species with the same two species of the genus Augite-spar, with which they agree so nearly in many of their properties, will af- ford in future an excellent test for the correctness of their determination. GENUS II. DISTHENE-SPAR. 1. PRISMATIC DISTHENE-SPAR. Prismatic Kyanite. JAM. Syst Vol. II. p. 94. Man. p. 134. Kyanite. Cyanite. PHILL. p. 81. Cyanit. Rhaetizit. WERN. Hoffm. H. B. II. 2. S. 313. IV. 2. S. 128. Kyanit. HAUSM. II. S. 636. Disthen. LEONH. S. 422. Disthene. HAUY. Traite', T. III. p. 220. Tabl. comp. p. 54. Traite', 2de Ed. T. II. p. 357. Fundamental form. Scalene four-sided pyramid of unknown dimensions, the axis of which is in- clined in the planes of both diagonals. Vol, I. Fig. 42, PHYSIOGRAPHY. Simple forms. ! (P) = 73° 45' PHILLIPS; Char, of Comb. Tetarto-prismatic. Inclination of ?£ upon r F+Q0. = 93° IS' PH. 2 r 2 Combination. l.£» r P + ^ fr+oo. Fig. 82. 2 ^ Cleavage, f r -f oo highly perfect and easily ob- tained, less distinct r — i_?., least of all _I. Fracture uneven. Surface, streaked parallel to the common edges of intersection, between the forms. Lustre pearly upon ?r -f , particularly if pro- duced by cleavage; inclining to vitreous, or vi- treous upon the rest of the faces, the former particularly upon faces of cleavage parallel to "*" Qp> if they are easily obtained. Colour generally white, often passing into blue,, some- times inclining to green or grey. Frequently spots of berlin-blue elongated in one direction, upon a paler ground. Streak white. Transpa- rent ... translucent. Brittle. Hardness = 5-0 . . . 7-0; the lowest degrees upon Pr + oo, the highest on the solid angles and edges. Sp. Gr. = 3-675, a blue, transparent variety, cut and polished; 3-559 a milk-white variety of Rhaetizite. ORDER VI. PRISMATIC DISTHENE-SPAR. Compound Varieties. Twin-crystals: faces of composition parallel, axis of revolution perpendicu- lar to ?r + oo. Massive : composition broad co- lumnar, sometimes straight lamellar, often curved or divergent ; faces of composition in most cases ir- regularly streaked. OBSERVATIONS. 1. The two varieties formerly distinguished as particular species, which the prismatic Disthene-spar comprehends, are Kyanite and Rhcetizite, but they are so nearly allied to each other, that the colour is the only property in which they can be said to differ, the latter of them referring to those varieties whose colour is white, without any deline- ations of blue. 2. Three varieties of the present species, analysed, the first by SAUSSURE, the second by LAUGIER, the third by KLAPROTH, have yielded, Alumina 54-50 55-50 55-50. Silica 30-62 38-50 43-00. .Lime 2-02 0-50 0-00. Magnesia 2-30 0-00 0-00. Oxide of Iron 6-00 2-?5 0-50. Water 4-56 0*75 0-00. Potash 0-00 0-00 a trace. It is not altered on being exposed to heat, and is infusible even in very high degrees of temperature. The Rhaeti- zite becomes first red, but again white, if further heated. They are difficultly, but entirely soluble in borax. Some crystals exhibit positive, others negative electricity, on be- ing rubbed, and to this property in particular the name Disthcne refers, given by HAUY to the present species. 3. The varieties of prismatic Disthene-spar occur in crys- tals, or massive, imbedded in rocks, as gneiss, mica slate, &c. The former are often accompanied by prismatoidal Garnet, united with them in a remarkable manner. It is found 216 PHYSIOGRAPHY. C.LASS ij. also in beds along with rhombohedral Quartz, dodecahedral Garnet, and several species of Augite-spar and Schiller- spar. In single small crystals it is met with in the rock called w) 'dtc-stone. 4. Crystals and large cleavable varieties are found at St Gothard in Switzerland, the Zillerthal in the Tyrol, the Saualpe in Carinthia, the Bacher mountain in Stiria. It is likewise met with at Langenloys in Austria, at Sebes in Transylvania, in Bohemia, Moravia, and Saxony ; in Banff- shire in Scotland, and in various places of North and South America, in Siberia, &c. The llhaetizite is chiefly known from Pfitsch in the Tyrol. 5. Thin laminae of this mineral are sometimes employed as a support in making experiments before the blowpipe. Blue transparent varieties are cut and polished, and then sometimes sold as an inferior kind of Sapphire, which is a variety of rhombohedral Corundum. GENUS III. TRIPHANE-SPAB. 1. PRISMATIC TRIPHANE-SPAR, Prismatic Spodumene. JAM. Syst. Vol. II. p. 91. Man. p. 135. Spodumene. PHILL. p. 142. Spodumen. WERN. Hoffm. H. B. II. 1. S. 341. Triphan. HAUSM. II. S. 526. Triphan. LEONH. S. 484. Triphane. HAU y. Traite', T. IV. p. 407- Tabl. comp. p. 37. Traite7, 2de Ed. T. III. p. 134. Fundamental form. Scalene four-sided pyramid of unknown dimensions ; so are also simple forms and the character of combinations. Cleavage, P + oo = 93° BROOKE ; £ r + oo rather more distinct. Fracture uneven. Lustre pearly. Colour various shades of greyish- green ; passing into greenish-white. Streak white. Translucent. ORDER vi. AXOTOMOUS TRIPHANE-SPAR. 217 Brittle. Hardness = 6-5 . ., 7-0. Sp. Gr. = 3 170, a variety from Uton. Compound Varieties. Massive : composition gra- nular, of various sizes of individuals, generally large. OBSERVATIONS. 1. According to ARFVEDSON, the prismatic Triphane- spar consists of Silica 06-40. Alumina 25-30. Lithia 8-85. Oxide of Iron 1-45. If exposed to a red heat, it loses transparency and colour. Before the blowpipe it iutumesces, and then melts into a nearly colourless transparent glass. 2. It occurs in primitive rocks, massive, and engaged in rhombohedral Quartz, along with rhombohedral Tourma- line, prismatic Feld-spar, &c. 3. It was first discovered at Uton in Siidermanland, Sweden ; but has afterwards been found also at Sterzing iji the Tyrol, and Killiney in Ireland. & AXOTGMOUS TRIPHANE-SPAK. Prismatic Prehnite. JAM. Syst. Vol. I. p. 338. Axoto- mous Prehnite. Man. p. 136. Prehnite. PHILL. p. 36. Prehnit. WERN. Hoffm. II. B. II. \. S. 220. Prehnit. HAUSM. II. S. 560. Prehnit. L.EONII. S. 442. Preh- nite. HAU Y. Traite', T. III. p. 167- Tabl. comp. p. 50. Traite, 2de Ed. T. II. p. 603. Fundamental form. Scalene four- sided pyramid, whose dimensions have not been exactly ascer- tained. Vol. I. Fig. 9. Simple forms. P — oo (P) ; P ; P + oo (M) = 99° 307 (nearly) ; Pr = 90° (nearly) ; Pr + oo {&) ; f r + n (o) = 31° (nearly) ; ?r + oo (/). 218 PHYSIOGRAPHY. CLASS II. P + oo. Dauphiny. P + oo. Pr + oo. oo. Char, of Comb. Prismatic. Combinations. 1. P — oc. 2. P — oc. Pr + oo. Dauphiny. 3. P — oo. f r -f n. P + oo. Fig. 13. Ratschinges, Tyrol. Cleavage. Very distinct in the direction of P — oo ; less easily obtained parallel to P -f- oo. Surface P — oo streaked parallel to the edges of combina- tion with Pr, often divided in two faces, meeting at a very obtuse angle of about 177° 30'. P and Pr are smooth, the rest of the faces streaked par- allel to their edges of combination with P — oo. Lustre vitreous, except upon P — oo, which pos- sesses pearly lustre, particularly if produced by cleavage. Colour various shades of green, as leek-green, mountain-green, apple-green, siskin- green, &c. ; passing into white and grey. Streak white. Semi-transparent ... translucent. Brittle. Hardness = 6-0 ... 7<0. Sp. Gr. = 2-926, a greenish-white cleavable variety. Compound Varieties. Reniform, globular, sta- lactitic shapes : surface generally drusy ; composi- tion columnar, sometimes broad, imperfect, and strongly coherent ; if the particles of composition be distinct, the surface is often pretty smooth. Massive: composition either columnar, as above, or granular, and even sometimes impalpable. Some- times compound varieties are again aggregated in a second composition, the faces of composition being rough and uneven, OADZB VI. AXOTOMOUS TRIPHANE-SPAR. 219 OBSERVATIONS. 1. The mechanical composition of the different varieties of the present species has given occasion for dividing it into two sub-species. Individuals and massive varieties cf a granular composition are foliated Prehnite ; while imita- tive shapes and massive varieties exhibiting a columnar composition, are called fibrous Prehnite. 2. From two analyses, one of them referring to a variety from the Cape by KLAPROTH, and the other to a variety from Reichenbach in the Palatinate by L.AUGIER, it ap- pears that the chemical composition of axotomous Triphane- spar is as follows : Silica 43-83 42-50. Alumina 30-33 28-50. Lime 18-33 20-40. Oxide of Iron 5-66 3-00. Water 1-83 2-00. Potash and Soda 0-00 0'75. Before the blowpipe it is transformed into a white frothy scoria, and then melts into a compact coloured globule ; with borax it melts into a transparent bead. In dilute mu- riatic acid it is slowly dissolved, and leaves a flaky residue. It shews electric poles when heated. 3. Axotomous Triphane-spar is met with in various re- positories. It occurs in veins in primitive mountains, with prismatic Axinite, several species of Augite-spar, with prismatic and tetarto-prismatic F eld-spar, and other spe- cies. It is found in beds with octahedral Iron-ore and some species of the order Pyrites. It is very frequent in trap- rocks of all ages, particularly the newer ones, either in amorphous masses, or in very irregular veins, and in ve- sicular cavities, with various species of the genus Kouph- one-spar, sometimes with octahedral Copper. 4. It was first brought to Europe by Colonel PREHJJ from the Cape of Good Hope, in bright coloured apple- f green varieties. Since that time it has been discovered in 220 PHYSIOGRAPHY. CLASS il. crystallised and massive varieties, in the alps of Savoy and Dauphiny, in St Gothard in Switzerland, in the Tyrol, in Salzburg, Carinthia, in the Pyrenees, in Norway and Swe- den. It is found in considerable quantity near Glasgow in Scotland, also at Reichenbach near Oberstein in the Pala- tinate, in the Faroe islands, in America, &c. GENUS IV. DYSTOME-SPAR. 1. PRISMATIC DYSTOME-SPAR. Prismatic Datolite. JAM. Syst. Vol. I. p. 345. Man. p. 139. Datholite. Boi ate of Lime. PHILL. p. 1 77. Datholith. WERN. Hoffm. H. B. III. 1. S. 143. Datolith. HAUSM. III.S.865. Datolith. LEONH. S. 588. Chaux boratee siliceuse. HAUY. Tabl. comp. p. 17. Traitd, 2de Ed. T. I. p. 590. Humboldtite. LEVY. Ann. of Phil. Febr. 1823. p. 130. Id. PHILL. p. 380. Fundamental form. Scalene four-sided pyramid. p= * , 133° 47, 77°41'- Inclina- , tion of the axis = 1° 41' 30", in the plane of the long diagonal. Vol. I. Fig. 41. LEVY.* * The angles of incidence and dimensions of the regular forms of the present species are those given for Humboldtite by Mr LEVY ; as calculated from the angles given for the sub- stance, Pr = 115° 45', P + ca = 77° 30' and the inclination of the axis = 1° 41' 30". There can be no doubt, that the crys- tals represented in Figs. C8. 69. and 70., from the collection of the Johanneum at Gratz, are this same Humboldite, which Mr MOHS recognised to be Datolite, from the comparison of the rest of their characters, particularly hardness and specific gra- vity. Also the varieties from Arendal frequently possess a hemi-prismatic character, as is evident from Fig. 67. The po- sition in which Mr LEVY compared the crystals of Datolite with those of Humboldite is different from that adopted in the present work. The want of symmetry in those of Datolite, as referred to his Fig. 2., is contiguous to the opposite acute lateral edges of m = 76° 35', a prism which agrees in position ORDER VI. PUISMATIC DYSTOME-SPAR. a : b : c : d = 33-8 : C7'17 : 53-95 : 1. Simple forms. P— 00(6); -H ? j ^ } = (Pr)5 ,.. (P)5 , — — - (*) ; — ~ ( 43° 56'; ftr+ oo (5); Pr (^ = 115° 45'; | Pr + 1 (r) = 93° 26'; Pr + 1 (o) = 77° # ; Pr + or> (w). Char, of Comb. Hemi-prismatic. Inclination of P — CD on f r + QD = 91° 4V 30". Combinations. 1. P — oo. -. . Pr+1.. P + oo. (**_+_?)!, ?r -f oo. Fig. 67. Arendal, Norway. / of the figures, and with his prism el = 77° SCX in Humboldtite, while the prisms a1 = 115° 3^ in Datolite, and m = 115° 45' in Humboldtite, also possess a similar situation, that of d in the figures. The difference in the angles, particu- larly the incidence of P — cs on P + cs, giyen as 90° in Da- tolite, and 91° 41' 30" in Humboldtite, remain to distinguish the crystals of the two bodies ; but a new comparison of them, under this point of view, would yet be desirable. Their hemi- prismatic character was first given in the Characteristic of the Natural History System of MOHS, the angles, from want of other measurements, were indicated upon the authority of HAUY. Also the variety from America is decidedly hemi- prismatic. H. VOL. 11. 223 PHYSIOGRAPHY. CLASS II. p _ P -f- oo. (?r + oo)3. Fig. 68. Theiss near Brixen, Tyrol. S.P_W. |. *L+1 - tome-spar, but which do not yet allow us to draw any de- cisive inferences, in regard to the determination of the species. 2. According to KLAPROTH, the simple varieties of Da- tolite, and the compound ones of Botryolite, consist of SOica 36-50 36-00. Lime 35-50 39-50. Boracic Acid 24-00 13-50. Oxide of Iron 0-00 1-00. Water 4-00 6-50. The chemical fomula of the first is Ca B4 + Ca Si2 -f 2, Aq, that of the second Ca B2 + Ca Si2 + 2 Aq. Exposed to the flame of a candle, it becomes friable. Before the blowpipe it loses its transparency, intumesces and melts into a glassy globule. It is easily soluble in nitric acid and leaves a siliceous gelatine. PHYSIOGRAPHY. CLASS II. 3. It occurs in beds of iron-ore in primitive rocks, ac- companied by rhombohedral Lime-haloide, sometimes also by octahedral Fluor-haloide, several species of the genus Augite-spar, rhombohedral Quartz, and axotomous Tri- phane-spar. With the latter, and several species of Kouph- one-spar, it is found in agate-balls and irregular veins traversing trap-rocks. 4. Upon the beds of iron-ore described above, the varie- ties of Datolite and Botryolite are met with at Arendal in Norway. In agate balls the Humboldtite occurs in the Seiseralp in the Tyrol, in irregular veins in greenstone, in Salisbury-craig near Edinburgh, and in America. GBNUS V. KOtJPHONE*-SPAR. 1. TRAPEZOIDAL KOUPHONE-SPAR. Dodecahedral Zeolite or Leucite. JAM. Syst. Vol. I. p. 351. Trapezoidal Zeolite or Leucite. Man. p. 141. Leucite. PHILL. p. 107. Leuzit. WERN. Hoffm. H. B. I. S. 482. Leuzit. HAUSM. II. S. 588. Leuzit. LEONH. S. 459. Amphigene. HAUY. Traite', T. II. p. 559. Tahl. comp. p. 33. Traite\ 2de Ed. T. III. p. 61. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple form. Ci (g) Vol. I. Fig. 34. Irregular forms, grains. Cleavage very imperfect, parallel to the hexahedron and the dodecahedron. Fracture conchoidal. Surface of crystals even, though generally rough, of grains uneven and smooth. Lustre vitreous. Colour reddish-, yellowish-, or greyish- white ; ash-grey or smoke-grey. Streak white. Semi-transparent ... translucent. From xcv$9?, light. ORDER VI. DODECAHEDRAL KOUPHONE-SPAR. Brittle. Hardness = 55 ... 6-0. Sp. Gr. = 2-483, a semi-transparent yellowish-grey variety. Compound Varieties. Massive: composition granular ; faces of composition irregularly streaked. Hare. OBSERVATIONS* L The tessular form is given here on the authority of HAUY. According to the observations of Dr BREWSTEB, this species possesses two axes of double refraction, and must therefore be considered as one of those instances in which we have to look forward to future observations, that may enable us to account for this apparent exception to the general law, that tessular forms are connected with that structure which possesses no double refraction. 2. The trapezoidal Kouphone-spar is composed of From Vesuviu?. From Albano. Silica 53-750 54-00 56-10. Alumina 24-G25 23-00 23-10. Potash 21-350 22-00 21-15. Oxide of Iron o-ooo o-oo 0-90. KLAFROTH. ARFVEDSON. Its chemical composition is K3 Si4 + 6 Al Si2, or in words, 20-89 potash, 22 76 alumina, and 56-35 silica. Alone it is infusible before the blowpipe : but it fuses with borax or carbonate of lime, though with difficulty, into a clear globule. Reduced to powder it changes the colour of the blue tincture of violets into green. 2. This species occurs chiefly in imbedded crystals and grains in lava, sometimes in compound varieties in the specimens ejected by Mount Vesuvius. Besides this lo- cality, it is also found at Albano and Frascati near Rome. 2. DODECAHEDRAL KOUPHONE-SPAR. Soda'ite. JAM. Syst. Vol. II. p. 52. Dodecahedral Zeo- VOL IT. P 226 PHYSIOGRAPHY. CLASS II. lite. Man. p. 142. Sodalite. PHILL. p. 127- Sodalit. HAUSM. II. S. 524. Sodalit. LEONH. S. 457. Soda- lite. HA Y. Traite; 2de Ed. T. III. p. 59. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H; D, Vol.1. Fig. 51. Vesu- vius. Combination. 1. H. D. Fig. 151, the faces of the hexahedron very small. Greenland. Cleavage, dodecahedron perfect. Fracture con- choidal, uneven. Surface smooth, sometimes rather uneven. Lustre vitreous. Colour green, greenish-white, passing into greyish- and snow-white. Streak white. Translucent. Brittle. Hardness = 5-5 ... 6'0. Sp. Gr. = 2-295, crystals from Greenland. Compound Varieties. Massive : composition granular ; faces of composition uneven. OBSERVATIONS. 1. Two analyses of the present species, one by ECKE- BERG, another by THOMSON, have yielded Silica 36-00 38-52. Alumina 32-00 27-48. Lime 0-00 2-10. Oxide of Iron 0-15 1-00. Soda, and a little Potash 25-00 23-50. Muriatic Acid 6-75 3-00. Volatile substances 0-00 2-10. Its chemical formula is Na3 'Si2 + 4 Al Si, which corres- ponds to 27-62 of soda, 30-25 alumina, and 42-13 silica. Before the blowpipe it melts, with intumescence and de- velopement of air bubbles, into a colourless glassy globule : with borax it melts difficultly, but only if added in a small OHDEBVI. HEXAHEDRAL KOUPHONE-SPAR. proportion. The fresh fracture of the Greenland variety often presents a beautiful crimson-red tint, which, however, soon fades, the mineral being exposed to light, as has been first observed by Mr ALLAN. 2. The dodecahedral Kouphone-spar is found in West Greenland, in a bed in mica-slate, from six to twelve feet thick, and is accompanied by several species of the genera Augite-spar and Feld-spar, also by pyramidal Zircon and Eudialyte. It occurs likewise among the minerals ejected by Mount Vesuvius. 3. HEXAHEDRAL KOUPHONE-SPAR. Hexahedral Zeolite, or Analcime. JAM. Syst. Vol. L p. 355. Man. p. 142. Analcime. PHILL. p. 129. An- alzim (Cubizit). WERN. Hoffm. H. B. II. 1. S. 251. Analzim. HAUSM. II. S. 586. Analzim. LEONH. S. 458. Analcime. HAUY. Traite', T. III. p. 180. Tabl. comp. p. 51. Traite', 2de Ed. T. III. p. 170. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H. (P) ; D Vol. I Fig. 31.; Ci (o) Vol. I. Fig. 34. Kollefiord, Stromoe, one of the Faroe islands. Char, of Comb. Tessular. Combinations. 1. H.Ci. Fassa, Tyrol. Fig. 153. 2. H. D. Ci.* Vesuvius. Cleavage, hexahedron difficultly obtained ; ano! even when distinct, of a very interrupted appear- ance-f-. Fracture imperfect conchoidal, uneven. * This rare and new variety is preserved in the cabinet of Mr ALLAX. H. •f I have observed it in some translucent varieties in TVfr ALLAN'S collection ; the transparent ones present more perfect- ly conchoidal fracture. Dr BRE WSTER has found that the crys- tals of this substance are composed in a singular manner" of PHYSIOGRAPHY. CLASS n Surface in general smooth, faintly streaked par- a allel to those edges of the icositetrahedron, which meet in the solid angle of three faces, often they appear a little convex. Lustre vitreous. Colour white, prevalent, passing into grey, more frequently into reddish-white and flesh-red. Streak white. Transparent ... translucent. Brittle. Hardness = 5-5. Sp. Gr. =2-068, crys- tals from the Tyrol. Compound Varieties. Massive: composition gra- nular, of various, often considerable sizes of indi- viduals, more or Jess strongly coherent. Faces of composition uneven and rough, and often irregu- larly streaked. OBSERVATIONS. 1. VAUQUEEIN has found a variety of the present spe- cies to consist of Silica 58-00. Alumina 18-00. - Soda 10-00. Lime 2-00. Water 8-50. Its chemical constitution is expressed, according to BERZE- LIUS, by N3 Si4 4- 6*A Si2 + 12 Aq, which corresponds to twenty -four solids, such as would arise from laying planes par- allel to those of the dodecahedron through their centres ; each of them on the surface of Fig. 34. Vol. I. being contiguous to the solid angle a, to one of those marked 6, and to two adjacent ones marked c. These solids are symmetrically arranged in respect to the axes of the icositetrahedron ; but each or them possesses a separate optical structure, and a double refraction, as if modified by a succession of strata of variable density. H. ORDER VI. PARATOMOUS KOUPHONE-SPAK. 229 13*73 of soda, 22-55 alumina, 55-84 silica, and 7*90 water. Upon charcoal it melts without intumescence or ebullition, into a clear, a little vesicular, glassy globule, and gelati- nises in muriatic acid. 2. The hexahedral Kouphone-spar chiefly occurs in the cavities of amygdaloidal rock, and several kinds of basalt ; less frequently it is found in small irregular veins, and in a few rare instances, in beds and veins belonging to more ancient rocks. In the first of these they line the sides of the cavities, or fill them up altogether. It is accompanied by various other species of the present genus, particularly the prismatic and pyramidal Kouphone-spars. In beds it occurs along with dodecahedral Garnet, several species of Augite-spar and Iron-ore, rhombohedral Lime-haloide, &c. ; the latter species, and paratomous and prismatoidal Kouph- one-spar, are found with it in metalliferous veins. 3. Fine, and particularly large crystals of the present species, are found at the Seiser Alp in the Tyrol, at Dumbar- ton in Scotland, near Almas and Tokoro in Transylvania, &c. Other varieties of it are found in several parts of Scot- land, particularly in the Western isles ; also in the Faroe islands and in Iceland ; near Catania, at Monte Somma, in the Cyclopic islands, &c. It is met with in the ironstone beds of Arendal in Norway, and in the silver veins of An- dreasberg in the Hartz. 4. PARATOMOUS KOUPHONE-SPAR. Pyramidal Zeolite or Cross-Stone. JAM. Syst Vol. I. p. 362. Pyramido-prismatic Zeolite or Cross-Stone. Man. p. 143. Harmotome. PHILL. p. 56. Kreuzstein. WERN. Hoffm. H. B. II. 1. S. 261. Harmotom. HAUSM. II. S. 557. Harmotom. LEONH. S. 451.. Harmotorae. HAUY. Traite', T. III. p. 191. Tabl. comp. p. 52. Traite, 2de Ed. T. III. p. 142. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. 230 PHYSIOG11APHY. CLASS II. Simple forms. P (P) ; Pr (s) ; ?r + 2 (0 ; ?r+oo(o); Pr+oo (g). Char, of Comb. Prismatic. Combinations. 1. P. Pr + oo. Pr -f x. Sim. Fig. 10, without P. Oberstein, Deuxponts. 2. Pr. P. Pr+x. ?r-f oo. Strontian, Scotland. 3. ?r. P. Pr -f 2. Pr + smooth, but in most cases di- vided into four faces meeting at very obtuse angles, as in certain hexahedral varieties of octa- hedral Fluor-haloide. Lustre vitreous. Colour white prevalent, passing into grey, yellow, red, and brown. Streak white. Semi-transparent ... translucent. Brittle. Hardness = 4-5. Sp. Gr. — 2 392, crys- tals from Andreasberg. Compound Varieties. Twin-crystals. Face of composition parallel, axis of revolution perpendicu- lar to one of the faces of P + QD. The individuals are continued beyond the face of composition, and produce the common cruciform crystals, one of which is represented in Fig. 40. Massive : com- position granular, rare. ORDER VI. PARATOMOUS KOU PHONE-SPAR. 231 OBSERVATIONS. 1. The dimensions of the crystalline forms of this spe- cies have not yet been ascertained with sufficient exact- ness. As a point of comparison, the isosceles pyramid of 121° 58', 86° 36', given by HAUY, may be useful, although it supposes the prism P + os to be a rectangular four-sided prism, like that produced by the enlargement of o and q. Mr PHILLIPS finds the edge replaced by the horizontal prism Pr to be = 119° 4', and the angle of that prism it- self = 110° 26', from which two data the other terminal edge of P would follow 121° 6'; 2. According to KLAPROTH, the paratomous Kouphone- spar consists of Silica 49-00. Alumina 16-00. Baryta 18-00. Water 15-00. Alone upon charcoal it melts, without intumescence, into a clear globule. It phosphoresces with a yellow light, and is not easily acted upon by acids. 3. Paratomous Kouphone-spar occurs pretty frequently in metalliferous veins, but is found also in vesicular cavi- ties of amygdaloidal rocks, like most other species of the present genus. The crystallised varieties in cruciform twins from Andreasberg in the Hartz, and in simple crys- tals from Strontian hi Scotland, are very generally known. They occur in metalliferous veins, traversing greywacke- rocks, accompanied by rhombohedral Lime-haloide, hexa- hedral Lead-glance, and in the first locality, also by pris- matoidal Kouphone-spar. This species is likewise met with in veins traversing mica-slate and hornblende-slate, with ores of silver, &c. 3. Besides Andreasberg and Strontian, veins are the re- positories of the present species at Kongsberg in Norway. It is very frequent in amygdaloid, as in various places in Scotland ; at Oberstein in Deuxponts, where it is found in the agate balls ; in Baden ; near Engelhaus and Buchau in Bohemia, and in the vicinity of Mount Vesuvius. PHYSIOGRAPHY". 5. HHOMBOHEDRAL KOUPHONE-SPAR. Rhombohedral Zeolite, or Chabasite. JAM. Syst. Vol. I. p. 359. Man. p. 145. Chabasie. PHILL. p. 138. Seha- basit. WERN. Hoffin. H. B. II. 1. S. 257. Chabasin. HAUSM. II. S. 585. Chabasie. LEONH. S. 449. Cha- basie. HAUY. Traitt^, T. III. p. 176. Tabl. comp. p. 50. Trait^, 2de Ed. T. III. p. 163. Fundamental form. Rhombohedron. R = 94° 46'. Vol. I. Fig. 7. PHILLIPS. a = ^/ 3-538. Simple forms. R — 1 (n) = 125° 13' ; II (P), Faroe; II + 1 (r) = 72° 53'; P + oo (u). Char, of Comb. Rhombohedral. Combinations. 1. R — 1. R. R -f 1. Fig. 120. Oberstein, Bavaria. 2. R — 1. R. R + 1. P 4- oo. The indivi- duals in Fig. 173. Giant's Causeway, Ireland. Cleavage, R9 pretty distinct. Fracture uneven. Surface, R — 1 and P -f oo streaked parallel to the edges of combination with R ; R -f 1 smooth. The faces of R are generally streaked parallel to their own terminal edges, which striae are pro- duced by a scalene six-sided pyramid having ter- minal edges of about 173J° and 103 J°, in paral- lel position with R. Lustre vitreous. Colour white, little modified. Streak white, Semi-transparent ... translucent. Brittle. Hardness = 4-0 ... 4-5. Sp. Gr. = 2-100, crystals from Bohemia. Compound Varieties, Twin-crystals. 1. Face ORDER VI. HHOMBOHEDRAL KOUPHONE-SPAR. 233 of composition parallel, axis of revolution perpen- dicular to R — oo, the individuals being continued beyond the face of composition. Fig. 128. Aussig, Bohemia; Fig. 173. Giant's Causeway. 2. Face of composition parallel, axis of revolution perpen- dicular to one of the faces of R, the individuals ter- minating at the face of composition. Fassa, Tyrol. Massive : composition granular, of various sizes ; feces of composition uneven. OBSERVATIONS. 1. According to the optical researches of Dr BREWSTEE, the rhombohedron, given above as the fundamental form of rhombohedral Kouphone-spar, is composed in a remark- able symmetrical manner of several solids, possessing each of them two axes of double refraction. They are often disposed in laminae round a kernel, which has only one optical axis, coincident with the principal axis of the rhom- bohedron. 2. According to VAUQUELIN, the present species con- sists of Silica 43-33. Alumina 22-60. Lime 3-34. Potash with Soda 9-34. Water 21-00. Alone before the blowpipe it melts into a white spumous mass, and is not acted upon by acids. 3. Also this species occurs, like several others of the present genus, chiefly in the cavities of amygdaloidal rocks, the sides of which are often coated with Green-earth. It is accompanied by other species of the genus Kouphone- spar, by rhombohedral Lime-haloide and rhombohedral Quartz. It occurs also in narrow veins in different trap rocks. PHYSIOGRAPHY. CLASS II. 4. The largest and most distinct crystals are found in Iceland, the Faroe islands, and the vicinity of Aussig in Bohemia. It is contained in the agate balls of Oberstein in Deux Fonts. Various simple and compound varieties occur in the Tyrol and other places in Germany, in Scot- land and particularly the Western Isles, in Ireland, &c. 6. DIATOMOUS KOUPHONE-SPAR, Di-prismatic Zeolite or Laumonite. JAM. Syst. Vol. I. p. 365. Diatomous Zeolite or Laumonite. Man. p. 146. Laumonite. PHILL. p. 45. Lomonit. WERN. Hoffm. H. B. II. 1. S. 26?. Laumonit. HAUSM. II. S. 555. Laumontit. LEONH. S. 448. Zeolite efflorescente ? HAUY. Traite, T. IV. p. 410. Laumonite. Tabl. comp. p. 19. Traite, 2de Ed. T. III. p. 151. BOURNON. Trans. Geol. Soc. Vol. I. p. 77- Fundamental form. Scalene four-sided pyramid. Inclination of the axis in the plane of the long diagonal. Vol. I. Fig. 41. Simple forms. P + oo (M) - 86° 15'*; + ^L { P \ ; — g i c J ?r + co (*) ; Pr + QD (/). Char, of Comb. Hemi -prismatic. Inclination of ?£ to P + x = 113° SO'*; of — ^ to P + v> Pr Combinations. 1. — . P -f GO. Fig. 44. Iceland. 2. JT . P + GO. Pr +00. Pr + oo, Schemnitz, Hungary. * According to BROOKE and PHILLIPS. OllDER vi. DIATOMOUS KOUPHONE-SPAR. 235 3. ?f. — If. P -f oo. Pr + x. Huelgoet, Brittany. Cleavage, Pr + GO distinct ; traces of Pr + oo. Fracture uneven, scarcely observable. Surface, ?r either smooth or uneven. The faces parallel 2 to the principal axis striated in that direction. Lustre vitreous, inclining to pearly upon the more distinct faces of cleavage. Colour white, pass- ing into some reddish, yellowish, or greyish tints. Streak white. Translucent. Not very brittle. Hardness unknown. Sp. Gr. = 2-3, HAUY. Compound Varieties. Massive : composition gra- nular, commonly elongated in one direction, faces of composition generally streaked. OBSERVATIONS. 1. According to two analyses, one by L. GMELIN, and another by VOGEL, the present species consists of Silica 48-30 49-00. Alumina 22-70 22-00. Lime 12-10 0-00. Water 16-00 17'50. Carbonic Acid 0-00 2-50. Before the blowpipe it gives the same results as the pre- ceding species. It gelatinises with acids, and acquires neg- ative electricity by friction, if isolated. It is decomposed by the action of the atmosphere, and loses its water ; it is therefore generally met with in a friable state, and most of its properties are on that account but imperfectly known. 2. It occurs in veins traversing clay-slate, with rhombo- 236 PHYSIOGRAPHY. CLASS 11. hedral Lime-haloide. Along with the same species it is likewise found in irregular veins and imbedded masses in porphyry, and in the cavities of amygdaloidal rocks. 3. The first variety noticed of this species Avas discovered by GILLET LAUMONT, in the lead mines of Huelgoet in Brittany, and has received its name in compliment to the discoverer. It was afterwards found near Schemnitz in Hungary in porphyry. It occurs likewise in Mount St Gothard with rhombohedral Fluor-haloide, in Faroe, Ice- land, and various parts of Scotland and Ireland. 7. PRISMATIC KOUPHONE-SPAll. Prismatic Zeolite or Mesotype. JAM. Syst. Vol. I. p. 368. Man. p. 146. Mesotype. PHILL. p. 123. Faserzeo- lith (in part). WERN. Hoffm. H. B. II. 1. S. 233. Zeolith (in part). HAUSM. II. S. 564. Mesotyp (in part). LEONH. S. 452. Mesotype. HAU Y. Traite', T. III. p. 151. Tabl. comp. p. 48. Traite, 2de Ed. T. III. p. 179. Fundamental form. Scalene four-sided pyramid. P = 142° 20', 142° 40', 53° 20'. Vol. I. Fig. 9. R. G. a : b : c = I : V8'°7 : A/7'794. Simple forms. P (o) ; P + oo (Jf ) = 91° 0' ; Pr + oo (r). Char, of Comb. Prismatic. Combination. P. P -j- oo. Cleavage, P -f- oo, perfect. Fracture conchoidal, uneven. Surface, Pr -f oo, vertically streaked, the rest of the faces smooth. Lustre vitreous. Colour, few shades of white, generally greyish, Streak white. Transparent . . . translucent. Brittle. Hardness = 5-0 ... 5-5. Sp. Gr. = 2-249. Compound Varieties. Implanted globular shapes : ORDER VI. PRISMATIC KOUPHONE-SPAE. 237 surface drusy, composition columnar. Massive : composition columnar, consisting of delicate, straight, and generally divergent individuals, radiating from a centre ; sometimes aggregated into angulo-granu- lar masses. Spheroidal shapes formed in vesicular cavities. OBSERVATIONS. 1. Mr PHILLIPS has given the first good representation of a crystal belonging to the present species, greatly re- sembling that of Fig. 174. The inclination of 6 on & has been found = 146° 16', e on M = 117° 14', while that of o on M is = 116° 40'. The only variety to which the pre- ceding description and the characters of the Characteristic refer, is that from Auvergne. However similar in various respects it may be to other varieties, as to those from Ice- land, Scotland, the Tyrol, Faroe, and other localities ; yet it cannot be united with them within one and the same species, on account of the difference of several of their properties. The real difference between several of them have been sufficiently demonstrated by the labours of Pro- fessor FUCHS, Dr BREWSTER, Mr BROOKE, Mr PHIL- LIPS, &c. ; and no doubt an accurate investigation of all the physical properties of these substances will enrich the remarkable genus of Kouphone-spar, with several new species. From this investigation it will also appear which of the various kinds of Mesotype must be united with the present species. • * The angle of the prism M is given in the variety from Auvergne 9 1° 20' 9 1° 1 0'. Hogau (Xatrolite) 91° 35' 91° W. Iceland (Mesolite) 91° 22' PHILLIPS. 91° 20'. BROOXE. From various observations I have found the first of these from 90° 59' to 91° 3', the third from 91° 23' to 91° 27'; moreover, a variety from Faroe =91° 28' — 91° 29', and one from the district of Maloa in East India = 91° 23'. 238 PHYSIOGRAPHY. CLASS IT. 2. Several analyses have been published referring to the varieties formerly comprehended within the Mesotype of HAUY. Thus Messrs GEHLEN and FUCHS, who first dis- covered the difference among several of these substances, obtained from Scolezltc Mcsolite Natrolite from Staffa. from Iceland. r'rom Hohentwiel. from Tyrol. Silica 46-75 47-46 47-21 48-63 Alumina 24-82 25-35 25-60 24-82 Soda 0-39 4-87 16-12 15-69 Lime 14-20 10-04 0-00 o-oo Water 13-G4 12-41 8-88 9-60 Oxide of Iron 0-00 0-00 1-35 0-21 With these analyses, other varieties have been found to agree more or less. The chemical formula of Natrolite is given by BERZELIUS Na3 Si 3 + 2 Al Si + 4 Aq, which cor- responds to 15-93 of soda, 26-19 alumina, 48-64 silica, and 9-24 water. The Natrolite loses its transparency before the blowpipe, and melts into a glassy globule ; the radiated va- rieties exfoliate, and the compact ones intumesce. They are with difficulty soluble in borax. Some of them assume, by heat, faint degrees of opposite kinds of electricity on their opposite ends, and become positively electric by friction. 3. The general repository of ail the species here under consideration, are the vesicular cavities of amygdaloidal rocks. They are accompanied by various species of the present genus, and by rhombohedral Lime-haloide. Some Fig. 175. represents a crystal of the Iceland variety ; there is a face of composition passing through the crystals, which therefore appear to be twins. This composition has been first observed by Dr BREWSTER. I obtained by measure- ment the incidence of o of one individual, on the face o" of the other = 1 79° 0' of o on o' = 141° 53', of o" on o' = 142° 53'; o on the adjacent face over a = 145° 10'. The edges marked a, and those between o and M, are often replaced, by additional faces, the first of which are striated parallel to the edges of combination with 0, the latter rough. H. ORDER vi. PRISM ATOIDAL KOU PHONE-SPAR. 239 varieties of Natrolite occur in veins traversing clinkstone, others in amygdaloid. 4. The variety of Mesotype, to which the preceding ge- neral description refers, is found in several localities near Clermont-Ferrand in Auvergne. Other varieties occur in Iceland, the Faroe islands, Tyrol, Italy, the Lipari islands, &c. ; the Natrolite is met with at Hohentwiel in Swabia, and at Bilin in Bohemia, some varieties of it also in the valley of Fassa in Tyrol, &c. 8. PRISM ATOIDAL KOUPHONE-SPAR. Prismatoidal Zeolite or Stilbite (Radiated Zeolite). JAM. Syst. Vol. I. p. 378. Man. p. 149. Stilbite. PHILL. p. 37. Strahlzeolith. WERST. Hoffm. H. B. II. 1. S. 237. Blattrich-strahliger. Stilbit. HAUSM. II. S. 575. Stilbit (in part). LEONH. S. 445. Stilbite (in part). HAUY. Traite', T. III. p. 161. Tabl. comp. p. 48. Traite', 2de Ed. T. III. p. 155. BROOKE, Edin. Phil. Journ. Vol. VI. p. 112. Fundamental form. Scalene four-sided pyramid. P = 119°15',11400',96°0'. Vol. I. Fig. a BROOKE. a : b : c = 1 : V 1-7502 : V 1-5087. Simple forms. P — oo (P) ; P (r) ; P + oo = 94° 15'. Pr + oo (T) ; Pr + QD (M). Char of Comb. Prismatic. Combinations. 1. P. Pr + oo. Pr -f oo. Iceland. 2. P — cc. P. Pr -f oo. Pr + x. Fig. 10. Faroe. 3. P— oo. P. P + oo. Pr + x. Pr + oo. Camp- sie, Stirlingshire. Cleavage, Pr + CD highly perfect, traces of Pr + oo. Fracture uneven. Surface, P — oo often curv- ed, Pr -f- oo vertically streaked, still more so Pr + QD. Lustre vitreous. The faces Pr 4- oo, both as fa- 240 PHYSIOGRAPHY. CLASS II. ces of crystallisation and of cleavage, exhibit per- fect pearly lustre. Colour white prevalent, va- rious shades, passing into yellow, red, and brown. Streak white. Semi-transparent ...translucent. Brittle. Hardness = 3-5.. .40. Sp. Gr. = 2-161, white crystals from Iceland. Compound Varieties. Twin- crystals : face of composition parallel, axis of revolution perpendicu- lar to one of the faces of Pr, the individuals are continued beyond the face of composition, so that the whole assumes a cruciform aspect.* The crys- tals are frequently aggregated in the form of sheafs. Implanted globules, surface very drusy, composi- tion imperfectly columnar, and strongly cohering. Massive : composition imperfect columnar, indivi- duals broad, straight, and radiating from a com- mon centre, strongly coherent. Often these com- positions are again aggregated into granular masses. Globular shapes formed in vesicular cavities. OBSERVATION'S. 1. The present species was first distinguished from the fol- lowing one, in the Characteristic of the Natural History Sys- tem. Their difference was afterwards pointed out by Mr BROOKE, who gave the latter species the name of Heulanditc. They are chiefly distinguished by their forms, which are prismatic in Stilbite, and hemi-prismatic in the Heulandite ; their hardness and specific gravity agree very near with each other. This difference in the forms is not only suffi- cient, but its necessary consequence is the perfect diversity * A beautiful crystal of this variety from Faroe, is pre- served in the cabinet" of Mr ALLAN. H. ORDER VI. PRISMATOIDAL KOUPHONE-SPAR. of the two species, because the fundamental forms in the two cannot be united by any regular geometrical process, and therefore belong to different systems of crystallisation. 2. According to HISINGER, the prismatoidal Kouphone- spar consists of Alumina 16-10. Silica 58-00. Lime 9-20. Water 16-40. Its chemical formula is Ca Si'2~f 2 Al Si3 + 12 Aq, which corresponds to 8-77 lime, 15-82 alumina, 58-78 silica, and 16-63 water. Before the blowpipe it yields an opake vesi- cular globule. It does not gelatinise with acids. 3. The varieties of the present species and of the fol- lowing one, agree very nearly in regard to their modes of occurrence in nature, and are rarely met with, except when accompanying each other. Their principal repositories are the vesicular cavities of amygdaloidal rocks, and certain metalliferous veins. In the first they are found deposited upon the walls, which have often a coating of green-earth, along with other species of the present genus, with rhombohedral Lime-haloide, rhombohedral Quartz, &c. Besides the metalliferous veins, where it occurs also with various Kouphone-spars, and with ores of silver and lead, it is found in metalliferous beds in primitive mountains, with ores of copper and iron, and several species of the genus Augite-spar. 4. Magnificent crystals of a white colour are met with in the vesicular cavities of the amygdaloids of Iceland and the Faroe islands. Similar varieties have been brought also from Indore in the Vendyah mountains in East India. Those from the Tyrol are mostly compound, and of a brick-red colour. Beautiful crystals of this colour occur near Campsie in Stirlingshire, though the present species is less common in Scotland and the Western Isles, than the following one. The crystals from the silver-veins of Andreasberg in the Hartz, are generally small, so are also those which occur in VOL. II. Q PHYSIOGRAPHY. GLASS II. the ironstone beds of Arendal in -Norway, and in the beds of copper-ore in the Bannat of Temeswar. 9- HEMI-PRISMATIC KOUPHONE-SPAR. Prismatoidal Zeolite or Stilbite (in part. Foliated Zeo- lite). JAM. Syst. Vol. I. p. 378. Henri-prismatic Zeolite. Man. p. 150. Heulandite. PHILLIPS, p. 38. Blatterzeolith. WERN. Hoffm. H. B. II. 1. S. 240. Bltittriger Stilbit. HAUSM. II. S. 573. Stilbit (in part). LEONH. S. 445. Stilbite (in part). HAUY. Traite', T. III. p. 161. Tabl. comp. p. 48. TraiteV 2de Ed. T. III. p. 155. BROOKE. Edin. Phil. Journ. Vol. VI. p. 112. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 41. Char, of Comb. Hemi-prismatic. The relations among the simple forms not being yet ascertain- ed with sufficient exactness, the 50th Figure may serve as a point of comparison for such va- rieties as may be found in nature. The following are approximate measurements nearly agreeing with Mr BROOKE'S, expressed in round num- bers : s on Tf = 114° 0', u on u = 146° 40', s on sf = 129° 40', z on z = 136° 0', s'on T =116° 20', x on x = 95° 0', x being two faces, which replace the edges between M and T, so as to produce an edge with w, which is parallel to that between u and s. Generally several crystals, very little divergent, are grown the one upon the other, in such a manner that the centres of M are deeper than its margins, which prevents them very frequently from being measured by means of the reflective goniometer. Cleavage, M, highly perfect. Fracture imperfect eonchoidal, uneven. Surface of all the forms ORDER VI. HEMI-PJIISMATIC KOUPHONE-SI'Ali. more or less uneven ; M often concave, s and s? convex. Lustre vitreous. The faces M possess high de- grees of pearly lustre, both as faces of cleavage and of crystallisation. Colour, various shades of white, prevalent, passing into red, grey, and brown. Streak white. Transparent ... translu- cent on the edges. Brittle. Hardness = 3-5...4-0. Sp. Gr, =± 2-200, white crystals from Iceland. Compound Varieties. Massive : composition granular, the individuals being of various sizes, sometimes easily separable, sometimes strongly co- hering ; faces of composition in most cases uneven and rough. Globules formed in vesicular cavities. OBSERVATIONS. 1. Of several of the older analyses of Stilbite, it i£ im- possible to say whether they refer to this or to the preced- ing species. LAUGIER obtained from 1., a red variety from the Tyrol, and WALMSTEDT from 2., a variety called Heulandite, the following results : Alumina 1. 10-00. 2. 7*19. Silica 45-00. 59-90. Carbonate of Lime 16-00. 0-00. Lime 11-00. 1G-87. Water 12-00. 13-43. Oxide of Iron 4-00. 0-00. Oxide of Manganese 0-50. 0-00. Before the blowpipe this and the preceding species give nearly the same results. 2. What has been said in general of the natural reposi- tories of the prismatoidal Kouphone-spar, refers also to the hemi-prismatic one ; they occur both in Iceland and the 244 PHYSIOGRAPHY. CLASS II. Faroe islands in beautiful crystals. The hemi-prismatic species is more frequently found in the Tyrol and in Scot- land than the prismatoidal one, while the reverse takes place in the Hartz and in Norway. It occurs in beautiful varieties in the Vendyah mountains in Hindostan. 10. PYRAMIDAL KOUPHONE-SPAR. Axifrangible Zeolite or Apophyllite (in part). JAM. Syst. Vol. I. p. 384. Pyramidal Zeolite or Apophyllite. Man. p. 151. Apophyllite. PHILL. p. 110. Albin. WERN. Syst. S. G. 37. Apophyllit (in part). LEONH. S. 590. Me'sotype e'pointee. HAUY. Traite, T. III. p. 154. Tabl. comp. p. 48. Apophyllite (in part). Traite, 2de Ed. T. III. p. 191. Fundamental form. Isosceles four-sided pyra- mid. P = 104° 2', 121° V. Vol. I. Fig. 8. HAUY. a = V 3-125. Simple forms. P — oo. (o) ; P — 3 (c) = 135° 59', 64° (X; P (P) ; ^ P — 3 (e) = 137° 55', 61°2'; 4 p— 5(6)^160° 15', 28° 4'; f P— 4 (d) = lM° 44', 38° 56' ; P + oo ; P + oo (m) ; [(P + oo)3] (r) = 143° 7 48", 126° 52' 12". Char, of Comb. Pyramidal. Combinations. 1. P. [P -f oo]. Fig. 97. Cziklowa, Bannat. 2. p_ oo. P. [P + GD]. Sim. Fig. 1 1. Fassa, Tyrol. 3. P. [P + ooj. [(P + oo)3]. Iceland. 4,. p—oo. fP—5. |P— 4. »V-ip— .3. P— a P. [P + oo]. [(P + oo)3]. Uton, Sweden. Cleavage. P — CD, highly perfect ; [P + oo] im- perfect. Fracture uneven. Surface, P — OD very smooth, shining and even ; P smooth, but frequently curved ; the obtuse pyramids are even, ORDER vi. PYliAMlDAL KOUPHONE-SPAR. 245 though generally rather rough, and | P — 4 ho- rizontally streaked ; the vertical prisms, particu- larly [P + oo] are streaked parallel to the axis. Lustre vitreous. The faces of P — oo, both in crystals, and as obtained by cleavage, possess common pearly lustre. Colour, several shades of white, greyish, blueish, or reddish, little dif- ferent. Streak white. Transparent ... translu- cent. Brittle. Hardness = 4-5 ... 5-0. Sp. Gr. = 2-335, a crystallised variety from Iceland. OBSERVATIONS. 1. The present species has not yet been sufficiently dis- tinguished from the following one, and it is even possible that they may constitute but a single one. It appears that they do not differ in regard to chemical composition, as will be seen in the Observations on the following species. 2. The natural repositories of pyramidal Kouphone-spar are much the same as 'those of the other species of the present genus, either in the vesicular cavities of amygda- loidal rocks with the same and with rhombohedral Lime- haloide, or in metalliferous beds with prismatic Augite- spar, rhombohedral Lime-haloide, Copper-pyrites, &c. 3. Some of the finest varieties are found in the amygda- loids of Iceland and of the Faroe islands. Likewise near Indore in India. This is also the mode of its appearance in nature near Aussig in Bohemia, whence the variety called Albine has first been noticed, and in New South Shetland. It occurs in the drusy cavities of a considerable and very extensive bed of limestone in gneiss, containing ores of copper, at Cziklowa near Orawitza in the Bannat. It is difficult to decide, whether some of the localities commonly quoted, belong to one or the other of these two species. 2) PHYSIOGRAPHY. CLASS II. 11. AXOTOMOUS KOUPHONE-SPAR. Axifrangible Zeolite or Apophyllite (in part). JAM. Syst. Vol. I. p. 384. Man. p. 151. Apophyllit. PHII.L. p. HO. Ichtbyophthalm. WEBN. Hoifm. H. B. II. 1. S. 357- Apophyllit. HAUSM. II. S. 580. Apophyllit (in part). LEONI?. S. 590. Apophyllite (in part). HAUY. Tabl. comp. p. 36. Traite, 2de Ed. T. III. p. 191. Fundamental form. Scalene four-sided pyramid. P =• 106° 52', 101° 37', 120° 34'. Vol. I. Fig. 9. HAUY. a : b : c = 1 : V 0-6923 : V 0-6154. Simple forms. P — oo (P), P (r) ; Pr + oo (M) ; Pr + (T). One of the combinations gene- rally quoted is represented Fig. 11. Cleavage, P — oo highly perfect, traces of Pr -f oo and Pr + oo. Fracture uneven, imperfect con- choidal. Surface, Pr + oo and Pr + oo faintly streaked in a vertical direction, P — oo parallel to the edges of combination with P. Lustre vitreous. It is pearly upon P — oc, both upon faces of crystallisation and of cleavage. Colour, several shades of white. Streak white. Transparent ... translucent. Brittle. Hardness = 4*5 ... 5-0. Sp. Gr. —2467, HAUY, OBSERVATIONS. 1. The forms quoted in the above description were for- merly given by HAUY for the variety of Apophyllite from Fassa in the Tyrol, but have since been abandoned by him in the second edition of his Traite, where he united all the varieties within a single species, having pyramidal forms. Dr BREWSTER has observed, that in certain va- ORDER VI. AXOTOMOUS KOUPHONE-SPAR. 247 rieties to which he has given tlie name of Tessclite, the phenomena of double refraction cannot be explained upon the supposition of a single axis, and that even the proper- ties of the mineral are not uniform in this respect through- out the whole mass, but that it appears composed of va- rious parts acting differently upon light. It will depend upon a future accurate examination of the crystalline forms and other properties of this substance, in comparison with these observations, whether they will concur in fixing the limits of the species, or whether this will depend solely upon the optical structure of the mineral. The varieties from Utb'n, and from the Seiseralpe in the Tyrol, evident- ly belong to the preceding species. 2. According to two analyses by BERZELIUS, referring to L, the Apophyllite from Utb'n, and 2., the Tesselite from Faroe, and one by STRO MEYER of 3., the variety from Greenland, the present species appears to consist of, Silica 1. 52-13 2. 52-38 3. 51-26. Lime 24-71 24-98 25-20. Potash 5-27 5-27 5-14. Tluoric Acid 0-82 0-64 0-00. Water 16-20 16-20 16-04. Its chemical formula, according to RERZELIUS, is K Si4 + 8 Ca Si2 +32 Aq, which corresponds to the ratios of potash, lime, silica, and water = 5-26 : 25-40 : 53-18 : 16-16, no attention being given to the small portion of fluoric acid. Before the blowpipe it first exfoliates, then intu- mesces like borax, and melts at last into a white vesicular globule. It is easily dissolved by borax. It is positively electrified by friction, not by heat. It likewise exfoliates in acids, and its powder forms a gelatine with them. 3. Like the preceding species, the present one occurs in vesicular cavities of trap-rocks, and in beds in ancient rocks, associated partly with other species of the present genus, particularly hexahedral Kouphone-spar, and with rhombo- hedral Quartz, partly with hemi-prisinatic Augite-spar, oc- tahedral Iron-ore, &c. 248 PHYSIOGRAPHY. CLASS II. 4. The localities quoted ave the Faroe islands, and seve- ral iron mines in Sweden and Norway. GENUS VI. PETALINE-SPAR. 1. PEISMATIC PETALINE-SPAR. Prismatic Petalite. JAM. Man. p. 152. Petalite. PHILL. p. 143. Petalit. LEONH. S. 485. Petalite. HAUY. Traitd, 2de Ed. T. III. p. 137. Fundamental form. Scalene four-sided pyramid of unknown dimensions. Simple forms, charac- ter of combinations, &c. unknown. Combinations not observed. Cleavage, a prism of 95° nearly, more distinct its long diagonal. Fracture imperfect conchoidai. Lustre vitreous, inclining to resinous ; it inclines to pearly upon perfect faces of cleavage. Colour white, in various reddish and greyish shades, sometimes inclining to green. Streak white. Translucent. Brittle. Hardness = 6-0 ... 6-5. Sp. Gr. = 2-439, a cleavable reddish-white variety. Compound Varieties. Massive: composition co- lumnar, of various sizes of individuals, sometimes impalpable and generally strongly coherent. If the composition be impalpable, fracture becomes splintery. OBSERVATIONS. 1. The cleavage of the present species is said by HAUY to take place parallel to the planes of a four-sided prism of ORDER VI. PRISMATIC 1'ETALINE-SPAB. 137° 10', and its short diagonal One of the faces of this prism is smooth and even, and easily obtained, the other is not so easily obtained, and possesses a kind of resinous lustre, similar to that face which passes through the diago- nal, though this seems not properly to be the diagonal of a rhombic prism. Since faces of different physical quality cannot belong to one and the same simple forms, it is ra- ther probable that those two less distinct faces produce a prism of about 95°, parallel to the long diagonal of which the more distinct face of cleavage is situated. More ac- curate examinations must decide, whether this more simple hypothesis, which has been introduced in the present work, be correct, or whether the forms of the species, as it is probable, possess a hemi-prismatic or tetarto-prismatic cha- racter. There are, moreover, traces of cleavage nearly perpendicular to the axis of this prism. 2. According to ARFVEDSON, the varieties of the pre- sent species consist of Silica 70-212. Alumina 17-225. Lithia 5-761. If exposed to a high degree of heat, before the blowpipe upon charcoal, it becomes glassy, semi-transparent and white, but melts vfiih difficulty, and only on the edges. If gently heated it emits a blue phosphorescent light. 3. The prismatic Petaline-spar has been hitherto found only in the Swedish island of Uton, where it is said by some to occur in a narrow vein traversing the beds of octa- hedral Iron-ore, which are worked in that place ; by others, in large boulders. It is accompanied by rhombohedral Lime- haloide, prismatic Feld-spar, rhombohedral Quartz, rhom- bohedral Tourmaline, &c. It has also been said to occur at the Lake Ontario in North America. 250 PHYSIOGRAPHY". CLASS II. GENUS VII. FELD-SPAR. 1. RIIOMBOHEDRAL FELD-SPAR. llhomboldal Felspar or Nepheline. JAM. Syst. Vol. II. p. 40. Man. p. 153. Sommite. PHILL. p. 125. Ne. phelin. WERN. Hoffm. H. B. II. 1. S. 365. Nephe- lin. HAUSM. II. S. 552. Nephelin. LEONH. S. 417. Nepheline. HAUY. Traite', T. III. p. 18G. Tabl. corap. p. 51. Traite', 2de Ed. T. III. p. 347. Fundamental form. Rhomb ohedron. R = 830£5'. Vol.1. Fig. 7. AP. Simple forms. R— oo(P); R+OD; P(r) = 139° 19', 88° 6'; P + 1 = 127° 16', 125° 30'; P + oo (M). Char, of Comb. Di-rhombohedral. Combinations. 1. R — oo. P 4- oo. Vesuvius. 2. R — oo. P. P + oo. Fig. 112. Cleavage, R — oo and P -f oo, both imperfect. Fracture conchoidal. Surface smooth and even. Lustre vitreous. Colour white. Streak white. Transparent ... translucent. Brittle. Hardness = 6-0. Sp. Gr. = 2-560. Compound Varieties. Massive : composition granular, of various sizes of individuals. Faces of composition rather rough. OBSERVATIONS. 1. Two analyses, 1. by VAUQUELIN, of a variety from Monte Somma, 2. by CARPI, of a variety from Capo di Bove, have yielded : Alumina 1. 49-00 2. 9-00. Silica 46-00 40-20. ORDER VI. PJIISMATIC FELD-SPAK. 251 Lime 2-00 20-80. Oxide of Iron 1-00 MO. Oxide of Manganese 0-00 12-60. Potash 0.00 12-00. Before the blowpipe upon charcoal its edges are rounded off. It yields a colourless vesicular glass, but cannot be melted into a perfect globule. Fragments of it thrown into nitric acid lose their transparency, and assume a nebu- lous appearance. This has suggested to HAUY the name of Nephdine. 2. Rhoinbohedral Feld-spar chiefly occurs at Monte Somma, in the cavities of limestone rocks ejected by Vesu- vius, along with pyramidal Feld-spar and Garnet, with rhombohedral Talc-mica, &c. It has also been found in narrow veins, traversing a kind of basalt or lava at Capo di Bove near Rome, sometimes associated with paratomous Augite-spar. 2. PRISMATIC FELD-SPAR. Prismatic Feld-spar. JAM. Syst. Vol. II. p. 1. Man. p. 154. Felspar. Ice-spar. Cleavelandite. PniLL.p. 113. 206. 377. Feldspath (Gemeiner Feldspath, Adular, La- brador, Glasiger Feldspath). Eisspath. WERX. Hoffm. H. B. II. 1. S. 295. 369. Feldstein. HAUSM. II. S. 528. Feldspath. LEONH. S. 468. Feldspath. HAUY. Traite', T. II. p. 570. TabL comp. p. 35. Traite' 2de Ed. T. III. p. 79. WEISS. Schv/eigger's Journal. X. 223. ID. Abhandl. der Acad. der AVissensch. in Berlin fur 1816 und 1817. FUCHS. Denkschr. der Adad. der Wissensch. zu Miin- chen, fur 1318 und 1819. G. ROSE, iiber den Feld- spath, Albit, Labrador und Anorthit. Gilberts Ann. der Phys. 1823. St. 2. Fundamental form. Scalene four-sided pyramid. P = 134° 57', 126° 12', 72° 43'. Inclination of the axis, in the plane of the long diagonal — 0° 0'. Vol. I. Fig. 41. R. Q. 253 PHYSIOGRAPHY. CLASS 11. a : b : c : d = 1 : ^4-419 z V 3-1C8 : 0. Simple forms. Z (s) = 126° 12'; -~ l?-1^ (ra) ; (Pr + OD)' (T, 1) = 118° 52' ; (Pr + oo)' '(«, *>) Char, of Comb. Hemi-prismatic. x^ Combinations. 1. — _. (fr+cx)5. Sim. Fig. 44-., reversed. St Gothard, Switzerland. g. ^. — ?!. (?r+ x)3. Sim. Fig. 1. StGothard. /w *v 3.^5.—^. (fr+QD)'. Pr+oo. Siberia. 4. S— ±^- - The individuals of Fig. 79. St Gothard. 6 *—— ^ - 1^±_? -?! ~2~ V "2* ~2 "2" (Pr + oo)5. (Pr+QD)5. Pr+QD. Fig. 62. Cleavage, — — highly perfect and easily obtain- ed. Pr -j- QD perfect, but often interrupted by conchoidal fracture, and less easily obtained. Traces of (Pr + cc)5, generally one of the faces a little more distinct, Fracture conchoidal... ORDER VI. PRISMATIC FELD-SFAR. 253 Pr uneven. Surface frequently streaked, — in a ho- rizontal direction, the vertical prisms parallel to the axis, so is also Pr -f- oo ; (Pr-j- GO) 5 is often rough. Most of the other faces are smooth. Lustre vitreous, sometimes inclining to pearly upon the perfect faces of cleavage. Colour white, prevalent, inclining to grey, green, or red ; some- times grey, flesh-red, verdigris-green. Streak greyish-white. Transparent, translucent on the edges. A blueish opalescence observable in the direction of Pr -f- OD, also sometimes of - — -— — : most distinctly in transparent varie- ties. The variety called Moonstone, from Cey- lon, appears considerably more red and of a lower degree of transparency, if viewed perpen- dicular to Pr + oo, than in any other direction. Brittle. Hardness = 60. Sp. Gr. = 2-558, a white transparent variety ; limits of the spe- cies = 2-53 ... 2-60. Compound Varieties. Twin-crystals. 1. Face of composition parallel, axis of revolution perpen- dicular to a face of — ^1. Fig. 79. If this mode of composition be repeated on all the faces of the same form, four-sided prisms consisting of four individuals will be formed, which are nearly rectan- gular, and bounded on their extremities by the faces of (£r + oc)3 and ?F, while the faces of — *1 2 2 constitute their apparently lateral planes, This PHYSIOGRAPHY. CLASS II. composition is frequently found in St Gothard. 52. Axis of revolution parallel to the principal axis, face of composition parallel either to the right. Fig. 80., or to the left faces, Fig. 81., of Pr + oo. Both are found near Elbogen in Bohemia. 3. Axis of revolution perpendicular, face of composition parallel to — ^ (HAUY. Traite. 2de Ed. T. III. p. 91. PI. 82. Fig. 256). 4. Axis of revolu- tion perpendicular, face of composition parallel to a face of — . This and the preceding variety are found at la C layette in the department of Saone and Loire in France ; a beautiful crystal of the latter is preserved in Mr ALLANS cabinet. Sometimes there occurs composition according to several of these laws at once. Massive : composition granular, of various sizes of individuals, sometimes lamellar. OBSERVATIONS. I. The forms, as contained in the preceding description, have been calculated from the observations of ~ being = 126° 12', and (Pr + cs)3 = 118° 52'. The inclination of the axis has been supposed = 0. It will depend upon future observations, whether this is in fact the case, or whether there exists also in the present species an inclina- tion, as in most other hemi-prismatic forms. The angle of (Pr + co)3 has been found in several varieties = 119° 10'. Besides the present species of prismatic Feld-spar, there are several whose forms possess a hemi-prismatic or tetarto- prismatic character, which differ so much in this respect, as well as in their angles, and the specific gravity, that ac- cording to the principles of Natural History, they must be considered as particular species. Their occurrence is most ORDER VI. TRISMATIC FELD-SPAR. 255 important in regard to the idea of genus in the Natural His- tory of the Mineral Kingdom, to which it imparts an addi- tional degree of evidence, and clearly demonstrates the ne- cessity of a systematic; nomenclature : for there can be as little doubt of their being particular species, as there can be of their being species belonging to one and the same genus, — Feld-spar. Mr G. ROSE has ascertained some of them with great precision, in the memoir quoted above. Inquiries of this kind are among the nicest in Mi- neralogy, and require great precautions to guard us from new species, whose admission might depend upon an er- ror of observation. These ought therefore to be often re- peated before finally settling the new species of the present genus. The following enumeration of some of them is intended merely for engaging mineralogists to inquire far- ther into their nature ; and I have therefore abstained from quoting any observations from the papers published on this subject. i. Alltte. The synonymes are included in those mentioned for prismatic Feld-spar. Fundamental form. Scalene four-sided pyramid, the axis of which is inclined in the planes of both diagonals. VoL L Fig. 42. Si-aplefonn, £ {?},_; 256 PHYSIOGRAPHY. CLASS IT. 2 4 Pr + co. Fig. 86. Measurements of angles : M on P = 93° 20', M on x = 93° 50', M on o = 113° 32', 71 on Z =121° 38'. The re-entering angles produced in Fig. 87. by P and P' measure 186° 40', those produced by a? and a/, 187° 40'. Cleavage, — __ perfect ; less distinct Pr 4- co ; the cleavage parallel to / _£jt_?L is sometimes more easily obtained 2 v » than either. Fracture imperfect conchoidal, uneven. Sur- face, the prisms parallel the axis streaked parallel to their Pr common intersections ; _ generally uneven or a little rough ; — r (-L 3/ rough, but very even. Lustre vitreous, often inclining to pearly upon perfect faces of cleavage. Colour white, passing into grey, red, and green. Streak white. Transparent, rare and only in small crystals, ... translucent on the edges. Brittle. Hardness = 6-0. Sp. Gr. = 2-613, small transpa- rent crystals from Dauphiny. Limits 2-61. ..2-68. Compound Varieties. Twin-crystals. 1. Axis of revolution parallel, face of composition perpendicular to Pr + co. Fig. 87. 2. Axis of revolution parallel to the edges of combination be- tween Pr + co and Pr -f co ; face of composition parallel to Pr -f co. The latter composition allows of two cases, and is similar to Fig. 80. and Fig. 81. It occurs frequently along with the preceding one, so that laminae of four individuals al- ternate with each other, composed parallel to Pr 4- co. All these compound and simple varieties have been observed in the varieties from St Gothard and Dauphiny. Massive : com- position granular of various sizes of individuals, sometimes compressed parallel to the faces of Pr 4- co or -- T, and then the composition assumes a lamellar appearance. OttDEK vi. PRISMATIC FELD-SPAR. 857 ii. Labradorite. The varieties of the present species differ but little from the preceding one, in regard to their geometrical proper. ties, at least their combinations likewise possess a tetar- to-prismatic character, and the angle at which the two more distinct faces of cleavage meet is also nearly 93° 30'. They present very frequently the same kinds of twin-crystals, or regular compositions. Their cleavage, particularly in the direction of Pr -f co, is less perfect than in most varieties of the two preceding species. The hardness is almost exactly identical, but the specific gravity of a variety from the coast of Labrador was found = 2*750. The limits are 2-69 ... 2-76. The remarkable opalescent and iridescent tints of colour appear most bright upon Pr + os, but they are also observed upon — ?£. The va- riety from Norway, commonly called Labradorite, in which the opalescence takes place in the direction of Pr + co, does not belong to the present species, but to that of prismatic Feld-spar. iii. Common Felspar from the Saualpe In Carinthia and from St Gotlwrd. Some of the varieties found in these localities seem to be- long likewise to a particular species. Their forms are te- tarto-prismatic, but differing as it seems in regard to their angles from Albite. Cleavage is much more easily observ- ed in the direction of — £5 and I (|!LifjlI. than in the 2 2 direction of Pr + co, which generally appears only in very slight indications. The specific gravity is equal to that of prismatic Feld-spar, the limits being 2-54 ... 2-56. This species occurs in very remarkable twin-crystals, some of them like Fig. 80 and 81, or Fig. 87, some like Fig. 88. In the latter the face of composition is parallel to — ?5, 2 while the axis of revolution is parallel to the edges of com- VOL II. R 258 PHYSIOGRAPHY. CLASS n. bination between _£ and — — , that is, to the line a b. 2 2 The degrees of transparency of the varieties hitherto ob- served are lower than those of prismatic Feld-spar or Albite. iv. Common Felspar from Baveno. These varieties are particularly distinguished from the rest by that highly perfect cleavage parallel to — _, which far surpasses the rest observable in the same species parallel to (£r + co)3, £r + cs and Pr -f co, and by their specific gravity, which is much inferior to all the species of the present genus, having been found in a crystal = 2-392. The limits appear to be 2-39 and 2-45. The combinations are hemi-prismatic, and from observations with the com- mon goniometer they seem not to be very different from those of prismatic Feld-spar. They possess very low de« grees of transparency, and often occur massive, having distinct lamellar particles of composition. In the older systems, all these different species, and moreover Chiastolite or Made, were comprised Avithin the common name of Felspar, and variously subdivided into sub- species and kinds. First those grey varieties which possess bright iridescent colours were separated from the rest, and established into a particular subspecies under the name of Ldbradore Felspar. It comprehends varieties of prismatic Feld-spar, and of Labradorite, as has been observed above. The most transparent and pure varieties, generally in im- planted crystals lining the walls of narrow veins in ancient rocks, were likewise considered as a particular subspecies, and called Adularia, in reference to the supposed oldest lo- cality known of this variety. It is made up of varieties of prismatic Feld-spar and of Albite. The less transparent varieties were divided into common and compact Felspar, the first of which contained, though not exclusively, easily cleavable crystals, the second imbedded crystals having no OBDEftVl. PRISMATIC FELD-SPAR. distinct cleavage, and compound masses of small or impalp- able and strongly connected individuals. Common Fel- spar contains varieties of all the species enumerated above, except perhaps Labradorite, which forms a great proportion of compact Felspar. From the latter subspecies, Clinkstone, which is commonly a mixed mineral, and forms the mass of porphyry slate, was distinguished as a particular species, and moreover Var\ol\te, consisting of small globular masses imbedded in a mixed rock. It has not been exactly ascer- tained to what species Clinkstone and Variolite belong, nor is it possible to settle at present any thing in this respect. Imbedded crystals of considerable degrees of transparency in porphyry slate, occurring also in various other trachytic and volcanic rocks, were called glassy Felspar. Their forms are generally hemi-prismatic, as in the examples from Drachenfels and Ischia ; but sometimes also tetarto-pris- matic varieties are observed in similar rocks, as in those from the Gallopago islands, brought home by Captain BASIL HALL. Ice-spar occurs in white transparent crys- tals, greatly resembling Adularia and glassy Felspar, but implanted in the drusy cavities of rocks ejected by Mount Vesuvius. However complicated this division may be, it is not all that was to be considered in the various kinds of Felspar. In regard to the particular state in which the varieties of common Felspar occur, those which are more or less decomposed, were designated by the denomination of earthy common Felspar, and considered as a particular subspecies. If the decomposition has arrived at its limits, so that the whole is converted into a more or less firmly coherent powder, Porcelain-Earth is formed. This substance is not only considered as a distinct species in the Werneriari system, but it is not even contained in the same genus with: the remaining subspecies. It is possible that porcelain earth arises from the decomposition of several species of the pre- sent genus, but we do not possess sufficient information in this respect. Professor FUCHS is of opinion that the porce- lain-earth from Passau is produced by the decomposition of 260 PHYSIOGRAPHY. CLASS n. what he calls Porcelain-spar, probably a variety of Labra- dorite. 2. Among several analyses referring to varieties of pris- matic Feld-spar, and the allied species of Albite and Lab- radorite, the following may serve for a comparison of their chemical constitution. Prismatic Feld-spar. Adularia, analysed Labradorite from Common Felspar from by Vauquelin. Norway, by Klaproth. Carlsbad, by Klaproth. 64-50. 19-75. 11-50. a trace. 1-75. 0-75. From Chesterfield in Massachusetts bj Stromeyer. 70-68. 19-80. 9-06. 0-23. Oxide of Iron and Manganese 0-00. 0-00. I'll. Ldbradorite. From Labrador by From Siebenlehn near Porcelain-spar from Klaproth. Freiberg by Klaproth. Passau by Fuchs. Silica 55-75. 51-00. 49-30. Alumina 26-50. 30-50. 27'90. Lime 11-00. 11-25. 14-42. Soda 4-00. 4-00. 5-46. Oxide of Iron 1-25. 1*75. 0-00. Water 0-50. 1-25. 0-90. The formulae of the composition of these three species, according to the method of BERZELIUS, are K S3 + 3 A S* Silica 64-00. 65-00. Alumina 20-00. 20-00. Potash 14-00. 12-25. Lime 2-00. a trace. Oxide of Iron 0-00. 1-25. Water o-oo. 0-50. Albite. From Finbo by From Arendal Eggertz. by Rose. Ma Silica 70-48. 68-84. Alumina 18-45. 20-53. With a little oxide of iron and lime- Soda 10-50. 9-12. Lime 0-55. 0-00. ORDER VI. PRISMATIC FELD-SPAE. 261 for prismatic Feld-spar, N S3 + 3 A S* for Albite, and N S3 + 3 C S3 + 12 A S for Labradorite. Before the blowpipe upon charcoal, prismatic Feld-spar becomes glassy, semi-transparent and white, but melts only with difficulty on its edges into a semi-transparent vesicular glass. It is dissolved by borax, but slowly and without effervescence, into a clear globule. The rest of the species agree in this respect with prismatic Feld-spar. They are not acted upon by acids, except Labradorite, which is entirely dissolved by heated muriatic acid. 3. The discovery of the difference among the preceding species is too recent to have yet been taken notice of in regard to the geological relations of what formerly used to be called Felspar ; so that wherever only Felspar is men- tioned, we must expect to find one or the other, or perhaps several of the species designated by that common name. Common Felspar frequently enters into the composition of rocks, and constitutes, with rhombohedral Quartz, and several species of the genus Talc-mica, the different kinds of granite and gneiss, with hemi-prismatic Augite-spar it forms syenite, green-stone, &c. Generally prismatic Feld- spar and Albite are found at the same time in granite, as in the varieties from Pompey's pillar, and from the block upon which the statue of Peter the Great in Petersburg!! is raised, the Albite being of a greenish-white colour, while the prismatic Feld-spar is flesh-red. Albite is most frequent- ly one of the constituents of syenite and greenstone, as in the neighbourhood of Dresden and Edinburgh. To several of these rocks large crystals of prismatic Feld-spar impart a porphyritic appearance; and it is a characteristic mark of the different kinds of porphyry more properly so called, to have isolated crystals of this species, and also of Quartz, Mica, &c. distributed throughout their compact mass: according to the latter, which in some cases, as in the clinkstone porphyry, itself belongs to the genus Feld-spar, they are distinguished and denominated. Compact Felspar (Labradorite) is fre- quently one of the constituents of greenstone slate, and a PHYSIOGRAPHY. CLASS n. compact variety perhaps of another species, the prevailing mass of Weissstein. Basalt, and some other rocks, allied with it, as wacke and graustein, must be considered as most intimate mixtures of prismatic Feld-spar or Albite with hemi-prismatic or with paratpmous Augite-spar, or with both these species, the individuals being so small as to be no longer recognizable. The two first have on that account been considered by mineralogists as particular species. In several of these rocks, which contain prismatic Feld-spar as one of their constituents, larger masses of it frequently form concretions separated from the rest, and assume the shape of more or less extended irregular beds. If these be decomposed by the action of the atmosphere, and their situation be favourable, Porcelain earth is formed, among the most remarkable of which we notice those in gneiss, at Aue near Schneeberg in Saxony, and at Hafnerzell in the district of Passau. At Carclaise and Cligga in Cornwall, the porcelain earth originates in the decomposition of gra- nitic rocks. Common Felspar frequently occurs in beds along with ores of iron and titanium, with several species of the genera Augite-spar and Garnet, &c., but it may be rightly considered as a rarity in veins, except in those which are composed of the same species of which the rocks consist which they traverse. In these its varieties are ac- companied by prismatic Axinite, rhombohedral Quartz, several ores of titanium, by rhombohedral Lime-haloide, and other species, and have their surface sometimes covered with scaly particles of prismatic Talc-mica. Sometimes hemi-prismatic crystals are covered with a tetarto-prismatic coat of another species, as in the varieties from Eaveno, which have Albite disposed in parallel position upon some of their faces, particularly upon Pr + co. Labradorite occurs in syenitic rocks, also as a regular constituent in several kinds of gabbro rocks, with hemi-prismatic Schiller-spar and Serpentine. Those crystals which give a porphyritic ap- pearance to the trachyte from the Drachenfels on the llhine, are considered as a variety of glassy Felspar. OBDEtt vi. PRISMATIC FELD-SPAll. 263 Among the most remarkable places of occurrence of some of the species of Feld- spars, certain meteoric stones deserve to be mentioned, as those which fell in 1807 at Stannern in Moravia, and those of 1821, at Aubenas (HAUY. Traite', 2de Ed. T. III. p. 537.) in France. In general, these spe- cies appear to have a considerable share in the composition of the meteoric masses. 4. The finest crystals of Adularia, both prismatic Feld- spar and Albite, are found in the highest districts of St Gothard and the Alps of Savoy, several varieties occur also in Salzburg, the Tyrol, Bavaria, Dauphiny, the isle of Arran, in Cornwall and Wales, &c. The largest crystals of Albite hitherto known are from Kerabinsk in Siberia. Also of the prismatic Feld-spar large crystals have been found in that country ; they are generally penetrated by rhombo- hedral Quartz, sometimes of considerable transparency. The twin-crystals from Carlsbad in Bohemia (Fig. 80. and 81.) are well known, and belong to prismatic Feld-spar. Amazone- stone, a verdigris-green variety of prismatic Feld-spar, often associated with small white crystals of Albite, occurs near Fort Troitzk in the Uralian mountains. Labradorite was first brought from the coast of Labradore ; it occurs also in Ingria, in large but not well defined crystals in Green- land, and as a constituent of several rocks in various places of the Hartz, Saxony, near Florence, &c. It has been observ- ed above, that what has been called Labradorite from Nor- way, in fact belongs to the species of prismatic Feld-spar; it occurs in the zircon-syenite of Friedrichsvarn. Com- pact felspar, forming the body of clinkstone-porphyry, is found in the Bohemian Mittelgebirge, in the Western Isles of Scotland, at Sahla in Sweden, in the Hartz, &c. Va- riolite has been noticed from Piedmont and Corsica. The finest varieties of Porcelain earth are those from China, where it is called Kaolin, from Saxony, from Passau, and from Limoges in France. The repository of porcelain- earth near Carlsbad in Bohemia, is of secondary formation, as it is there accompanied by basalt, clay, sandstone and coaL 5. Several varieties of the different species included in 261 PHYSIOGEAPIIY. CI,ASS n. the genus Feld-spar are used in the arts and manufactures. The purest opalescent varieties of Adularia are cut round and polished, and worn as ring-stones, &c. The finest of them are from Ceylon, and are called Moonstones. The Sunstone is likewise prismatic Feld-spar, having exceedingly minute scales of mica dispersed throughout its substance, which are disposed parallel to the face of Pr + co,and reflect a pinchbeck-brown tint. Labradorite, particularly the Ameri- can variety, and Amazone-stone, are cut for various orna- mental purposes, into snuff-boxes, &c. ; this is also the case with Graphic Granite, which consists of a simple varie- ty of common felspar, regularly mixed with long parallel cr}rstals of rhombohedral Quartz, whose transverse angular sections bear some resemblance to certain letters. The pure varieties of prismatic Feld-spar are used in the com- position of the paste of porcelain, also for the enamel with which it is covered ; and the decomposed variet}^ or Porce- lain earth itself is the most important material in that de- partment of manufactures. 3. PYEAMIDAL FELD-SPAR. Pyramidal Felspar or Scapolite. Prismato-pyramidal Fel- spar or Meionite. JAM. Syst. Vol. II. p. 35. 43. Py- ramidal Felspar. Man. p. 162. Dipyre. Scapolite. Meionite. PHILL. p. 45. 137. 143. Schmelzstein. Skapolith. Mejonit. WERN. Hoffm. H. B. II. 1- S. 270. 345. 3d. Tetraklasit. Meionit. HAUSM. II. S. 511.550. Wernerit. Mejonit. LEONH. S. 479. 481. Meionite. Wernerite. Dipyre. Scapolite. HA " Y. Traite, T. II. p. 580. T. III. p. 119. 242. T. IV. p. 393. Wernerite. Paranthine. Dipyre. Meionite. Tabl. comp. p. 34. 45. 55. Traite', 2de Ed. T. II. p. 582. 58G. 596. T. III. p. 75. Fundamental form. Isosceles four-sided pyramid. P = 136° r, 63° 48'. Vol. I. Fig. 8. R. G. a = V 0-3874. Simple forms. P — 1 (*) ; P (/) ; P + o> (») ; [P + oo ORDER TI. PYRAMIDAL FELD-SPAli. £65 Char of Comb. Pyramidal. Frequently single faces are irregularly enlarged at the expence of the rest.* Combinations. 1. P. P + CD. [P -f oo], Sim. Fig. 101. Akudlek, Greenland. 2. P — 1. P. P + oo. [P -f cc]. Sim. Fig. 102. Pargas, Finland. 3. P — 1. P. (P)3. P + QD. [P + oo]. Sim. Vol. I. Fig. 67. Vesuvius. 4. P. (P)5. P -f QD. [P -f oo]. (P + oo)5. Vesuvius. Cleavage, P -j- oo and [P -}- oo], distinct, but in- terrupted ; traces of P — oc, generally small conchoidal fracture in that direction. Fracture imperfect conchoidal, uneven. Surface of the prisms sometimes longitudinally streaked, but generally of nearly the same physical quality. Lustre vitreous, •inclining to resinous upon the cleavage, and fracture parallel to P — oo, in- clining to pearly upon P -j- Oo and [P + OD]. Colour, various shades of white, grey, and green. Red colours seem to arise from impurities. Streak greyish-white. Transparent ... translucent on the edges ; the red varieties are opake. Brittle. Hardness = 5-0 ... 5-5. Sp. Gr. =2-612, Meionite ; = 2-726, white crystallised Scapolite from Finland. * A crystal of the Scapolite, from Pargas, in the possession of Mr NORDEXSKIOLD, presents at one extremity only the alternating faces of (P)3, while the rest have disappeared. The opposite extremity could not be observed. H. PHYSIOGRAPHY. CLASS II. Compound Varieties. Massive : composition granular, of various sizes of individuals, sometimes elongated in one direction or wedge-shaped, and passing into columnar ; generally strongly coherent. OBSERVATIONS. 1. The varieties of the present species have been disco, vered at various periods, and in different kinds of reposi- tories. Some of them indeed, at first sight, appear so little resembling each other, that it is not to be wondered, that they were considered as particular species ; for in order to be certain in these determinations, a superficial inspection, or some information of the mode of occurrence or accom- panying minerals, cannot suffice ; even experiments before the blowpipe or the chemical analysis do not give that high degree of evidence which arises from an accurate examina- tion of the physical properties of minerals, of their form and cleavage, hardness or specific gravity; and this be- comes the more indispensable, if, as in the present case, the different varieties bear to each other but a slight degree of resemblance. Whatever may be the consequence of these examinations, it must always be a true, correct, and constant result, because it is founded upon those things which are constant in the productions of nature, their phy- sical properties. Mcionite contains the purest and most transparent varieties of the species of a white colour ; and it seems by these characters to be perfectly distinguished from the rest. Yet the varieties of Scajjolite from Finland, described by Mr NORDENSKIOLD, and those brought from Greenland by Sir CHARLES GIESECKE, possess the same pro- perties, though less distinctly, and unite Meionite with the rest of the varieties of Scapolite, which generally possess greenish colours, either pale and a little translucent, or dark, and then the crystals are very often nearly opake. Some of its varieties are coloured red, probably by oxide of iron. Upon this difference of colour, the division into red and grey Sea- OllDEH VI. PYRAMIDAL FELD-SPAB. 267 polite is founded. Among the varieties of the latter, there are some crystals, long and acicular and their composition columnar, possessing light shades of colour ; others which are short and thick, granularly compound, and of darker shades of colour. These two kinds have been distinguished by the names of radiated and foliated Scapolite. Dlpyie has been united with the present species, in reliance on those characters, which are quoted in most mineralogictl works ; it seems to differ from the preceding ones scarcely in any thing but in its reddish-white colour, and thin co- lumnar composition in massive varieties. Mr BROOKE, however, quotes a very minute crystal in his possession, too imperfect to be determined by measurement, but whose form he supposes to be the regular hexagonal prism, as it was first described by HAUY, and afterwards abandoned in consequence of renewed observations. 3. The following results were obtained, 1. by STROJIEYER, from a variety of Meionite from Monte Somma ; and 2. by NORDEXSKIOLD, from the Scapolite from Pargas. Silica 1. 40-531. 2. 43-83. Alumina 32-726. 35-43. Lime 24-245. 18-96. Potash and a little Soda 1-812. 0-00. Protoxide of Iron 0-182. 0-00. Water 0-000. 1-03. In a strong heat of the blowpipe, Scapolite melts into a vesicular glass, and intumesces considerably ; then it as- sumes the appearance of ice, and does not melt any longer. It is dissolved by borax with effervescence, and melts with it into a clear globule. Dipyre yields almost the same re- sults. 3. Meionite is met with among the minerals ejected by Mount Vesuvius, along with rhombohedral and prismatic Feld-spar, pyramidal Garnet, rhombohedral Talc-mica, &c. The varieties of Scapolite occur in primitive mountains, as in the beds of octahedral Iron-ore at Arendal in Norway, and in Wermeland in Sweden ; and are generally accompa- 2G& PHYSIOGRAPHY. CLASS II. nied by several species of the genera Feld-spar and Augite- spar. Scapolite has been found also in large and beautiful crystals in the parish of Pargas in Finland, at Akudlek in Greenland, and some varieties near Chursdorf in Saxony. Dipyre is hitherto confined to the Western Pyrenees, where it occurs near Mauleon under similar circumstances. GENUS VIII. AUGITE-SPAR. 1. PARATOMOUS AUG1TE-SPAR. Oblique-edged Augite. JAM. Syst. Vol. II. p. 99. Py- ramido-prismatic Augite. Man. p. 165. Augite. Py- roxene. PHILL. p. 58. Kokkolith. Augit. Diopsid. As- best (in part). Strahlstein (in part). Sahlit. Baikalit. Fassait. Omphazit. WERN. Hoffm. H. B. I. S. 443. 448. 467- II. 2. S. 277- 293. 319. IV. 2. S. 105. 111. 125. Pentaklasit. Asbest (in part). HAUSM. II. S. 687. 734. Augit. Asbest (in part). LEONH. S. 520. 533. Pyroxene. Malacolithe. HAUY. Traite', T. III. p. 80. IV. p. 379. Pyroxene. Tabl. comp. p. 41. Traite', 2de Ed. T. II. p. 407- Fundamental form. Scalene four-sided pyramid. P = 152° 12'; 120° 0'; 67° 4'. Inclination of the axis in the plane of the long diagonal = 0° 0'. Vol. I. Fig. 41. HAUY. a : b : c : d = 1 : ^12 : A/2'7692 : 0 Simple forms. P-oo(n); + = 81° 46'; (Pr -f oo)^ (M) = 87° 42'; — (M) = 131° 8' ; (o) = 35° 36'; (f + OD)S (/) = 141° 50'; Pr + oo (r); Pr 4- oo (/), ORDER vr. PABATOMOUS AUGITE-SPAR. 269 Char, of Comb. Hemi-prismatic. Inclination of (£r+ oo)3 = 101° 5'. Combinations. 1. — —. (Pr -f- oo)3. Sim. Fig. 44., reversed. Greenland. 2. — ~ ft- + oo. Pr + oo. Sim. Fig. 46., reversed. Elba. 3. — . (Pr + o>)3. £r + QD. Pr-f- oo. Fig.72. Etna. 58 4. ?L — ~ (Pr + oo)3. Pr + oo. Pr + oo. Piedmont. 5. *_r. J. (^.-^ -L^ 2222 2 Pr + oo. Pr + oo. Fig. 73. Fassa, Tyrol. 6. Lr. Z. 201 -Lr. -(?)!. (fr+oo)3. 222 2 2 (P + oo)6. Pr + oo. Pr + oo. Fig. 176. Ala, Piedmont. Cleavage, (f r + cc) 3 rather perfect, but interrupt- ed, also Pr + oo and Pr -j- oo; sometimes — from which the adjective paratomous has been derived. Fracture conchoidal, sometimes per- fect ... uneven. Surface, P — oo frequently un- even and curved, the vertical faces, particularly Pr + oo and Pr + QD, striated parallel to the axis, — .sometimes rough. 270 PHYSIOGRAPHY. CLASS II. Lustre vitreous, inclining to resinous. Colour green, often inclining to brown, and passing into grey and white, and also into black. Streak white . . . grey, corresponding to the colour. Faintly transparent ... opake. Brittle. Hardness rrs 5-0... 6-0. Sp. Gr = 3-349 an ash-grey variety ; — 3.327 Omphazite from the Saualpe ; = 3-327 Fassaite ; 3-274 a greyish- white variety compound in laminae parallel to Pr + oo ; = 3-233 a grass-green variety from the Bacher mountain in Lower Stiria. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendicu- lar to ?r -f- oo. Sometimes crystals of this kind are in cruciform aggregations. Massive varieties com- pound in the direction of — • — , as in Sahlite ; this must not be taken for cleavage, as it does not con- tinue throughout the whole mass, but only produces more or less thick laminae, often separated from each other by some extraneous substance : it often possesses a slight pearly lustre: there is also composi- tion parallel to Pr -f oo, as in Mussite. Massive : composition granular of various sizes of individuals, often but slightly cohering, but often also very inti- mately connected ; faces of composition rough. The individuals of lamellar and columnar varieties are in most cases easily separated, and present striated faces of composition. OBSERVATIONS. 1. According to the measurements of Mr BROOKE and- ORDER VI. PARATOMOUS AUGITE-SPAE. £71 Mr PHILLIPS, with the reflective goniometer, tte ang!e of (Pr + cc)3 is = 87° 5'. It will be interesting to ascertain how far the inclination of the axis extends to the forms of Pr - the present species. The incidence of — on Pr+ « is stat- 2 it ed in Augite by Mr PHILLIPS = 105° 20', that of — _ on Pr + cc = IOC3 15'. But the inclination of the two faces p of — is given = 120° 38', and the same inclination in — — also = 120° 38'. ?? on (Pr + as)3 = 100° 10'. The present species unites a large number of varieties, both simple and compound, among which there exist un- interrupted transitions ; and for this in particular it be- comes a most important subject in the study of Minera- logy ; and, above all, for ascertaining the idea of the natu- ral-historical species. But it is at the same time remark- able for the high degree of resemblance which it bears to the remaining species comprised within the same genus, particularly those of which a great many different va- rieties have been discovered ; and thus it likewise demon- strates the existence of the natural-historical genus in Mineralogy, which is formed by uniting those species, which, notwithstanding their marked differences from each other, are yet united by the highest degrees of resemblance. Hence, on one hand, the difficulties be- come evident which arise from dividing one species into several ; on the other hand, the easiness with which they may be confounded, if their characteristic properties be not properly attended to, of which but too many examples might be quoted from the writings and collections of che- mists and mineralogists. A close examination, according to the principles of Natural History, will prevent us from falling into the same errors. The most ancient of those species which have been distinguished within the species of paratomous Augite-spar is Augite, which comprehends al- most exclusively opake varieties, the colours of which are black or blackish-green. One of its subdivisions; foliated 2 . P11YSIOG11APHY. CLASS II. Augite, occurs in imbedded crystals. Conchoidal Augite re- fers to imbedded grains, whose fracture is perfectly con- choidal ; common Augite occurs also in grains, but. having an uneven fracture. Foliated Augite is transformed by decomposition, into those earthy masses which have been called crystallised Green -earth. Coccolite is of rather paler shades of green colours than the preceding varieties, and consists of very distinct granular particles of composition, which may be easily separated. The colours of SaJilite are ge- nerally paler green, and inclining to grey ; it is faintly trans- lucent on the edges, though there are some varieties of it as black and opake as Augite. It is compound parallel to the face of — — . If the colours become very pale, it passes into Diopside, which contains greenish-grey, greenish-white, &c., and semi-transparent crystals, or massive varieties also of pale colours, and compound parallel to the face of Pr 4- 03. The latter is also the case in those dark-green va- rieties of common Actinottte which belong to the present species. Baikalitc cannot be distinguished from Sahli te, even by such slight marks as those just quoted, and Fassaite is the name of those varieties which unite the green colours of Sahlite, or some that incline still more to yellow with crystalline forms, similar to those of Diopside. Omphazite is a compact leek -green variety, with an imperfect conchoi- dal or splintery fracture, and generally mixed with dode- cahedral Garnet. That variety of granular Actinolitc which belongs to the present species, and which has often been called green Diallagc, is grass-green, either crystallised or massive, and in the latter case it presents a granular struc- ture, or is composed parallel to _ or to Pr + cs, alternat- ing in layers with particles of the following species, of the same colour. Very delicate crystals produce a kind of Asbestus, which is different from the one in connexion with hemi- prismatic Augite-spar, and different also from Picros- mine, a species that will be noticed in the Appendix. 2. The following analyses will shew the range of the constituent parts in the present species. ORDER VI. PARATOMOUS AUGITE-SPAR. 273 White variety. Leek-green variety. Black variety, analysed bj Bonsdorf. by Rose. by Rose. Silica 54-83 54-08 53-36. Lime 22-19 23-47 22-19. Magnesia 18-55 11-49 4-99. Alumina 0-28 0-00 0-00. Protoxide of Iron 0-99 10-02 17-38. Oxide of Manganese 0-00 0-61 0-09. Loss by heating 0-32 0*00 0-00. It may be considered as a bisilicate of lime and magnesia, in Avhich part of the bases are replaced by protoxide of iron, part of the silica sometimes by alumina, which, in the conch oidal Augite from Sicily, amounts to 16-5. Before the blowpipe it melts pretty easily, and emits a few bubbles ; it finally yields a glassy globule, more or less intensely co- loured by iron. It is readily dissolved by borax. Several varieties of the present species have been obtained by way of fusion. Black crystals are not unfrequent among the slags from the iron furnaces in Sweden. They consist of bisilicate of iron. A white variety in perfect crystals has been obtained by Messrs BERTHIER and MITSCHERLICH, when mixing silica, lime, and magnesia, in the necessary proportion, and exposing this mixture in a charcoal crucible to the heat of the Sevres porcelain furnaces. Many va- rieties of Pyroxene, if melted and then allowed to cool slowly, crystallise and assume an appearance little different from what they had before. 3. Paratomous Augite-spar occurs in imbedded crystals, in various kinds of rocks, in basalt, lava, &c. ; also in beds in older rocks, both in crystals and compound massive va- rieties ; it enters into the regular mixture or composition of several rocks, as the pyroxene rock, some varieties of greenstone and basalt: it likewise is found in veins tra- versing primitive rocks. Foliated, conchoidal, and common Augite are found in the first kind of these repositories ; granular Augite, Coccolite, and Sahlite occur in the second, and are associated with ores of iron and titanium, with hemi-prismatic and prismatoidal Augite-spar, several species VOL. II. « PHYSIOGRAPHY. CLASS II. of Feld-spar, &c. Also Omphazite occurs in beds with rhombohedral Quartz, dodecahedral Garnet, hemi-prismatic Augite-spar, &c. Diopside occurs in veins traversing ser- pentine, with dodecahedral Garnet and prismatic Talc- mica, and Fassaite and Baikalite also seem to occur in veins, where they are accompanied by rhombohedral Lime- haloide. 4. The imbedded varieties of Augite are found almost in every kind of basalt, and those rocks which are allied to it. The largest crystals occur near Aussig in Bohemia, but it is met with besides in the Rhon and Vogel mountains in Germany, in France and Italy, in Scotland and its Western Isles, &c. ; granular Augite and Sahlite are chiefly obtained from Arendal in Norway, and Sahla in Sweden ; Baikalite from the mouth of the Sljumanka river that falls into lake Baikal. Diopside is found in Piedmont, Fassaite in the valley of Fassa in the Tyrol, and in the Bannat of Temes- war, Omphazite in the Saualpe in Carinthia, and near Hof in Bayreuth. The beautifully green varieties of granular Actinolite occur in the Bacher mountain in Lower Stiria, the crystallised Green-earth in the valley of Fassa in the Tyrol. Pyroxene rock occurs in the Pyrenees ; among those compound rocks, where it forms one of the constituents, we shall notice here only the greenstone from the celebrat- ed Meissner mountain in Hessia. That black mineral, which is discernible in some meteoric stones, for instance those which fell at Stannern in Moravia, likewise seems to be paratomous Augite-spar. These meteoric stones, and the above mentioned greenstone from Meissner, but for the coarser grain of the latter, possess a high degree of re- semblance to each other. &. HEMI-PRISMATIC AUGITE-SPAR. Straight-Edged Augite. Green Diallage. JAM. Syst. Vol. II. p. 117. 172. Axotomous Schiller-spar or Green Diallage. Hemi-prismatic Augite. Man. p. 130. 160. Hornblende. Smaragdite. Asbestus. PHILL. p. 63. 71. Hornblende. Asbest (in part). Strahlstein (in part). OHDEH vr. HEMI-PRISMATIC AUGITE-SPAR. 275 Tremolith. Karinthin. Kalamit. WERN. Hoffm. H. B. II. 2. S. 146. 277- 293. IV. 2. S. 103. 122. Hornblende. Strahlstein. Grammatit. Byssolith. As. best (in part). Smaragdit. HAUSM. II. 699. 722. 728. 733. 734. 740. Smaragdit. Hornblende. Asbest (zum Theil). LEONH. S. 517- 527. 533. Amphibole. Acti- note. Diallage verte. Grammatite. Asbest (in part). HAUY. Traite', T. III. p. 58. 73. 126. 227- 245. Amphibole. Diallage verte. Asbeste. Tabl. comp. p. 39. 46. 55. Traite', 2de Ed. T. II. p. 372. 454. 481. Fundamental form. Scalene four-sided pyramid P = 151° 8', 149° 38', 42° 22'. Inclination of the axis in the plane of the short diagonal = 0° (Y. Vol. I. Fig. 41. HAUY. a : b : c : d = 1 : V 14 : V 12-6875 : 0. Simple forms. 1 (r) = 149° 38' ; — lJL± J? ' (b) = 112° 63' ; &!!)- (iy = 101° 32' ; — — _(z)=123°4'; (Pr+ «,)» (M) = 124° 34' ; &£L (a) ; (Pr + oo)^ (c) m fpr + 2 it\ /5101T — "~1T" W 151° IT f r + QD (5) ; Pr + oo (a:). Char, of Comb. Hemi-prismatic. Inclination of — on (f r + oo)3 = 103° 13'. Combinations. 1. — _. (Pr+oo)5. Sim. Fig. 44., reversed. Arendal, Norway. 276 PHYSIOGRAPHY. CLASS n. 2. _. (Pr + x)3. Pr + x. Pr + x. Sim. Fig. 72. (Tremolite) St Gothard. 3.?.. — ^—. (Pr+x)3. Pr+OD. Fig. 74. 2 /w Teplitz, Bohemia. 4, ?_. VfZ, _^. (Pr+x)3. Pr+x. C% o i^> V * Pargas, Finland. 5. -. — ?£. — !t£21. (Pr + x)3. Pr + x. 222 Teplitz. 6 P |Pr + 2 (P)3 (Fr)5 _Pr .^(Pr)^ O O Q 6> O C) ?r + OD. Pr + oo. Fig. 76. Vesuvius. Cleavage, (?r + oo)5 highly perfect, less distinct Pr -f oo, least of all Pr -f- OD. Fracture imper- fect conchoidal, uneven. Surface, sometimes striated parallel to the axis ; sometimes all the faces are uneven. Lustre vitreous, inclining to pearly upon faces of cleavage in the varieties possessing pale colours. Colour, various shades of green, often inclining to brown ; there is an uninterrupted series into perfectly white and into black varieties. Streak greyish-white ... brown. Nearly transparent ... opake.* * There is sometimes a blue opalescence observable in the ODDER VI. HEMI-PRISMATIC AUGITE-SPAR. 277 Brittle. Hardness = 5-0 ... 6-0. Sp. Gr. = 3-167 basaltic Hornblende from Lower Stiria; 3-127 Carinthine ; 3-026, Actinolite from Zillerthal ; 3-006, blackish-green common Hornblende; 2-931 white Tremolite. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendicu- lar to ?r + QD. This composition is also observ- able in massive varieties, sometimes in very thin la- minae, having often some foreign substance, parti- cularly laminae of the preceding species, interposed between them. There is also composition parallel to — —. Massive : composition granular, individuals of various sizes, generally strongly cohering, and producing in the great a tendency to slaty fracture ; composition columnar, individuals of various sizes, sometimes very delicate, generally long, parallel, or diverging, and aggregated in a second granular composition. Compositions of short and irregular- ly distributed columnar particles possess in the great a slaty fracture. Very thin columnar composi- tion produces a silky lustre. OBSERVATIONS. 1. Hornblende, Actinolite, and Tremolite, together with direction of Pr + co. The varieties which present it are faint- ly translucent, and shew a pale brown colour in thin splinters, but appear dark grey in the mass. They were discovered at Kassigiengoit in Greenland by Sir CHARLES GIESECKE, and formerly considered as Hypersthene. Mr BROOKE first recog- nised them to belong to the present species. H- 278 PHYSIOGRAPHY. CLASS u. certain kinds of Asbestus, comprehend far the greatest number of varieties belonging to the present species. Horn- blende differs from the rest chiefly by its dark, blackish, or greenish colours, and is distinguished into three subspecies, lasaltic Hornblende, common Hornblende, and Hornblende slate. The first contains black imbedded and perfectly cleavable crystals; the second refers to those imbedded crystals in which cleavage is not so easily obtained ; it in- cludes besides all implanted crystals and massive granular or columnar varieties, except such as are black and easily cleavable, and which have been distinguished from the rest by the name of Carinthine. Hornblende slate compre- hends compound or even mixed varieties, consisting of con- fusedly aggregated columnar particles of composition, and possessing a slaty fracture. Actinolite includes the green varieties, frequently in acicular crystals, and has been sub- divided into common, glassy, asbestous, and granular Actino- lite. The varieties of the first subspecies are almost all paratomous Augite-spar, and have been mentioned in the preceding species. Glassy Actinolite contains crystals and columnar compositions of a green colour ; asbestous Actino- lite refers to capillary crystals and very thin columnar compositions, of other colours than white ; granular Acti- nolite comprehends grass-green varieties, whose composi- tion is granular. The varieties of Tremolite, similarly subdivided into subspecies, differ from the preceding ones, particularly by their pale green, grey, or white colours. Common Tremolite occurs in crystals, and in massive varie- ties of columnar compositions, which possess low degrees of transparency. More transparent varieties in similar com- positions, consisting of thin individuals, are called glassy Tremolite; asbestous Tremolite forms masses of very thin, capillary crystals, exactly like asbestous Actinolite. Cala- mite, which has but lately deen discovered, is an asparagus- green, translucent variety in imbedded crystals, in a kind of serpentine. Asbestous Actinolite and asbestous Tremo- lite form a passage into Asbestus, of which, however, it ORD£H VI. HEMI-PRISMATIC AUGITE-SPAK. 279 must be remarked here, that the greater part does not be- long to the genus Augite-spar. The passages demonstrate that there are varieties of Asbestus belonging to the pre- sent species, and moreover there are crystallised varieties, of common Hornblende, consisting in their interior or ter- minating on their ends in decided fibres of Asbestus in a parallel position. This is also the case in certain va- rieties of the preceding species ; and we are led to con- clude that the term Asbestus itself rather expresses the state of aggregation of several, than the substance of a distinct mineral. Asbestus in general has been divided into Amiantus, which consists of highly delicate fibres, often thinner than a hair, longitudinally cohering with each other, and easily separated ; into common Asbestus, relating to coarser varieties, more firmly cohering, and yielding splintery fragments ; into Rock-Cork , in which the particles are aggregated in a loose felt-like texture, no longer recog- nisable, or to be separated from the rest ; and into Rock- Wood or ligneous Asbestus, in which a texture of the pre- ceding kind, only more close, and resembling membranes, assumes the general appearance of wood. Green Diattage or Smaragdlte has been found (HAIDINGER, Trans. Roy. Soc. Edin. Vol. X. p. 127.) in some cases to consist of laminae of hemi-prismatic Augite-spar, with faces of composition pa- rallel to Pr + co, in others of the same alternating with laminae of paratomous Augite-spar, both often of bright green colours. This kind of composition of the two species is frequently found also in black varieties. Among the varieties of this and the preceding species, if compared with each other, we are struck with the perfect analogy of certain varieties distributed as it were in paral- lel series. Augite and Hornblende, Sahlite and Actinolite, Diopside and Tremolite, stand in these relations, and both series terminate in their respective kinds of Asbestus. 2. Of the following analyses, three have been published by BONSDOEF, the fourth by VAUQUELIN : 280 PHYSIOGRAPHY. CLASS 11. A white A green A black Sraaragdite var. var. var. from Corsica. Silica 60-31 46-26 45-69. 50-0. Magnesia 24-23 19-03 18-79. 6-0. Lime 13-66 13-96 13-85. " 13-0. Alumina 0-26 11-48 12-18. 11-0. Protoxide of Iron 0-15 3-43 7-32. Oxide of Iron 5-5. Protoxide of Man- ganese 0-00 9-36 0-22. Ox. of Copper 1-50. Fluoric acid 0-94 1-60 1-50. Ox. of Chrome 7'50. Water and foreign substances 0-10 1-04 0-00. Before the blowpipe it melts with difficulty, and a little in- tumescence, into a globule which is not clear, and variously coloured by iron or chrome, agreeably to the contents of the specimen. Also in borax it is but slowly soluble. 3. In its geological relations, the species of hemi-prisma- tic Augite-spar remarkably agrees with that of paratomous Augite-spar. Imbedded crystals of basaltic Hornblende are found like those of Augite, and frequently along with them in basalt and amygdaloidal rocks ; crystals of com- mon Hornblende and of Tremolite, also compound varieties of the latter occur in limestone rocks ; the former likewise in porphyry and granite. Common Hornblende, Actino- lite and Tremolite, particularly the asbestous varieties of the latter, occur in metalliferous beds in ancient rocks, with ores of iron and titanium, with Iron-pyrites, dodeca- hedral Garnet-blende, hexahedral Lead-glance, &c. Com- mon Hornblende also frequently enters into the composi- tion of rocks, as syenite, several kinds of greenstone, green- stone slate, &c. The finest varieties of Actinolite are found in imbedded crystals, or columnar compositions in talc slate ; and capillary crystals of it and of Amiantus line the sides of narrow veins in primitive mountains. Hornblende slate, and certain varieties of common Hornblende, often mixed with rhombohedral Quartz, several kinds of Mica, dodecahe- dral Garnet, Sac. form by themselves beds in primitive and transition mountains. Carinthine occurs in beds included ORDEft VI. HEMI-PRISMATIC AUGITE-SPAR. 281 in gneiss, consisting of rhombohedral Quartz, dodecahedral Garnet, prismatoidal Augite-spar, &c. ; Calamite in serpen- tine, along with imbedded crystals of rhombohedral Lime- haloide and octahedral Iron-ore. 4. Basaltic Hornblende occurs in great abundance, and in beautiful crystals, near Teising and Teplitz in Bohemia, in large cleavable masses also, though not in regular crys- tals, at Toplitza in Transylvania. Large and very distinct crystals of a black colour are found imbedded in granular limestone in Pargas in Finland. Crystals of common horn- blende are met with at Arendal and other places in Nor* way and in Sweden ; also imbedded in limestone, and of a green colour, at Pargas in Finland, from whence the name of Pargastte is derived. The crystals in the drusy cavities of the Vesuvian minerals, though small, are generally very distinct, and possess a high degree of lustre. Common Hornblende occurs massive at Breitenbrunn, Ehrenfrie- dersdorf, and other places in Saxony ; also in the Saualpe in Carinthia, &c. Here also the most distinct varieties of Carinthine have been found ; but at the same time perfect transitions into common Hornblende. Calamite has been discovered at Xormarken in Sweden. Many varieties of Actinolite are met with in Salzburg and the Tyrol, granu- lar Actinolite in the Bacher mountain in Lower Stiria, asbestous Actinolite at Breitenbrunn, Raschau, and Ehren- friedersdorf in Saxony. Common and glassy Tremolite occur at St Gothard, at Sebes in Transylvania, &c. always in granu- lar limestone or dolomite, asbestous Tremolite in Switzer- land, the Tyrol, the Bannat, at Langefeld in Saxony, and other places. Amiantus is found in great profusion in Corsi- ca, also in Piedmont, Savoy, Salzburg, and Tyrol, in Upper Hungary, and Silesia ; at Zoblitz and Waldheim in Sax- ony, where in some places there is also common Asbestus. Rock wood is still confined to Sterzing in the Tyrol, where it occurs in large masses in a metalliferous bed, often mixed with hexahedral Lead-glance. Rock Cork is found at Johanngeorgenstadt in Saxony, at Sahlberg in Sweden, in Moravia, Switzerland, and Spain, also at Portsoy, Lead- PHYSIOGKAPHY. CLASS II. hills, Wanlockhead, Strontian, and other places in Scot- land. Green Diallage, generally accompanied by dodeca- liedral Garnet, and Saussurite, enters the composition of Euphotide or Gabbro rocks, and occurs in Corsica, on Monte liosa, in the Bacher, and other places. 3. PRISMATOIDAL AUGITE-SPAE. Prismatoidal Augite. JAM. Syst. Vol. II. p. 160. Man. p. 177. Epidote. PHILL. p. 41. Pistazit. Zoisit. Pie- montischer Braunstein. WERN. HoiFm. H. B. I. S. 654. 665. IV. 1. S. 152. Epidot. HAUSM. II. 671. Epi- dot. LEONH. S. 438. Epidote. HAUY. Traite, T. III. p. 120. Tabl. comp. p. 43. Traite', 2de Ed. T. II. p. 568. WEISS. Abh. der Akad. der Wissensch. zu Berlin, fiir 1818 and 1819. HAIDINGER. Edinb. Phil. Journ. Vol. X. p. 305. Fundamental form. Scalene four-sided pyramid. P = | ™° 3^ | , 151° 3', 117° 33'. Inclination of the axis = 0° 33' in the plane of the long dia- gonal. Vol. I. Fig. 41. R. G. a : b : c : d = 105-0 : 216-8 : 66-6 : 1. Simpleform, P-, (J); ± "= (o) = 63° 8'; (P -f <*>)4 (h) - 101° 35'; + ?£ . |63°43'K Pr + 1 , _ ^0 „* - 164° 36'J' -g- l^_±^ (i) = 34°2r; ]Pr + oo (JW); Pr — 1 • (y) = 103° 3(X ; Pr (q) = 64° 46' ; f r + oo (P). Char, of Comb. Hemi-prismatic. Inclination of P — oo on f r + oo = 90° 33'. ORDER VI. PRISMATOIDAL AUGITE-SPAE. Combinations. 1. _. —. _ _. ?r + oo. Fig. 75. Great St Bernard. 2 P_-OO ?£ -Z -!* dV±-=Ll>!. 2 2* 2' 2 ?r -f- QD. Pr + oo. Dauphiny. — oo. Pr + oo. Dauphiny. 2 22 fr + oo. Fig. 77. Arendal, Norway. Cleavage, f r -f- oo perfect; — — less distinct. Fracture uneven. Surface, the horizontal prisms streaked parallel to the short diagonal of P, also P — oo and ?r -f oo streaked parallel to their common edges of intersection. In general the faces are smooth. Lustre vitreous, inclining to pearly upon perfect faces of cleavage and the corresponding faces of crystallisation. Colour, green and grey preva- lent. Among the most common shades of the first is pistachio-green : in general the green tints are more inclined to yellow than in the two pre- ceding species. The grey colours pass into white and a very pale flesh-red. Streak greyish-white. Semi-transparent .., translucent on the edges. 284 PHYSIOGRAPHY. CLASS II. Viewed in a direction parallel to the axis, the colour of the crystals contains less yellow than in the directions perpendicular to it. Brittle. Hardness = 6-0... 7'0. Sp. Gr. = 3-269, Zoisite from the Saualpe ; = 3-425, Pistazite from Arendal. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendi- cular to — — . This composition is very frequent, particularly among the varieties from Dauphiny. Several varieties consist of concentric coats, the outer ones of which being pealed off, leave a crystal with smooth faces. Massive : composition granu- lar, of various sizes of individuals, sometimes im- palpable, strongly connected : columnar, straight, and either parallel or divergent or irregular, and of various sizes of individuals. OBSERVATIONS. 1. The two species, Pistazite and Zoisite, comprehend- ed within the varieties of prisraatoidal Augite-spar, are easily distinguished by their colours. The colours of the first are green, those of the second are white and grey, but there are transitions in the colours of both. The varieties of the present species, though less comprehen- sive than the two preceding ones, form a series, the mem- bers of which are analogous to the varieties of these spe- cies. Thus Pistazite corresponds to the varieties called Augite, Sahlite, Hornblende, and Actinolite, while Zoisite answers to Diopside and Tremolite. This comparison ex- tends even to the fourth species or prismatic Augite-spar, whose varieties correspond to those called Diopside, Tre» ORDER VI. PRISMATOIDAL AUGITE-SPAR. 285 molite, and Zoisite ; and it is likely that this will be found to be true even to a greater extent, when more varieties of that species shall have been discovered. The light reddish- black variety from Piedmont (piemontischer Braunstein of WERNER, Epldote manganesifere of HAUY) is a variety of Zoisite impregnated with oxide of manganese*. 2. The chemical composition of prismatoidal Augite-spar has been found as follows : Zoisite Pistazite From the Saualpe. From Dauphiny. From Norway. Silica 45-00 37'00 37'00. Alumina 2900 27'00 21-00. Lime 21-00 14-00 15-00. Oxide of Iron- 3-00 17*00 24-00. Oxide of Manganese 0 -00. KL APR. l-50.DEscoT. 1-50. VAUQ. Before the blowpipe the varieties of the present species in- tumesce and partly exfoliate, but are difficultly fusible, and only on the thinnest edges, into a transparent glass. Those which contain more oxide of iron are more easily fusible than the rest. VTith borax, Pistazite likewise first intu- mesces, and then yields a clear globule. 3. Prismatoidal Augite-spar agrees in regard to its natu- ral repositories with some of the varieties of the preceding species. Pistazite occurs along with them, frequently and in fine varieties, in beds of octahedral iron-ore ; also in single drusy cavities of various rocks, without, however, entering into their composition as a regular ingredient. It is met with, besides, in narrow veins irregularly distribu- ted through the rocks, and contemporaneous with them ; also in distinct veins, where it is associated with prismatic * Zoisite is included in the present species, on the authority of HAUY, who states its forms to be identical with those of Epidote. Mr BROOKE has found a difference in this respect, namely, that the perfect cleavage bisects the obtuse angle of 1 1 6° SO' of a rhombic prism, which is probably oblique ; and that there are faces of cleavage inclined to the obtuse edges of that prism. This would render it necessary to consider Zoisite as a particular species. H. 286 PHYSIOGRAPHY. CLASS ii. Axinite, axotomous Triphane-spar, rhombohedral Quartz, Asbestus, and various other minerals. Zoisite is found in single crystals, and crystalline masses in beds with hemi- prismatic Augite-spar, dodecahedral Garnet, rhombohedral Quartz, prismatic Disthene-spar, &c., or it constitutes beds itself with prismatic Feld-spar, as in the Saualpe in Carin- thia, where it forms the repository of pyramidal Zircon. A reddish-white variety, consisting often of impalpable particles of composition, is found in the Radelgraben in Carinthia, along with prismatic Talc-mica, in primitive mountains. 4. Magnificent crystals of the present species are found at Arendal in Norway ; and the name of Arendalite has been given to these varieties, from their locality. Similar va- rieties occur also in Sweden. Very fine crystallised va- rieties are known from Switzerland, Piedmont, also from the Pyrenees and the Upper Palatinate, in which localities they occur in veins. Less distinct varieties of the Pista- zite occur in many countries, as, for instance, in the Sau- alpe, where certain varieties are found, which, by their colour, connect the Pistazite with the grey varieties of Zoisite. Beside's this locality, .Zoisite is also found in the Bacher mountain and Schwamberg Alpe in Lower Stiria, in the Fichtelgebiirge, and in the Tyrol. The red mangane- sian varieties occur at St Marcel in the valley of Aosta in Piedmont. 4. PRISMATIC AUGITE-SPAR. Prismatic Augite or Tabular Spar. JAM. Syst. Vol. II. p. 170. Man. p. 179. Tabular Spar. PHILL. p. 23. Schalstein. WERN. Iloffm. H. B. III. 1. S. 55. Ta- felspath. HAUSM. II. S. 583. Tafelspath. LEONH. S. 660. Spath en Tables. HAU Y. Tabl. comp. p. 66. Wol- lastonite. Traitd, 2de Ed. T. II. p. 438. Fundamental form. Scalene four-sided pyramids of imperfectly determined dimensions. Vol. I. Fig. 4& ORDER VI. PRISMATIC AUGITE-SPAE. 287 Cleavage, in the direction of two faces intersecting each other at angles of 95° 25', both being easi- ly obtained, but one of them more perfect and smooth. There are besides imperfect traces of cleavage in various directions, which render it probable that the forms of this species will be found hemi-prismatic or tetarto-prismatic*. Frac- ture uneven. Lustre vitreous, inclining to pearly, particularly upon the perfect faces of cleavage. Colour white, inclining to grey, yellow, red, and brown. Streak white. Semi-transparent ... translucent on the edges. Rather brittle. Hardness = 40... 5-0. Sp. Gr. = 2-805, of a brownish-white variety from the Bannat. Compound Varieties. Massive : composition lamellar, generally longish, and aggregated into a second large grained and angular composition ; strongly coherent. OBSERVATIONS. 1. A variety of the present species from Cziklowa has * A tetarto-prismatic crystal is quoted by Mr PHILLIPS. Comparing it with Fig. 82., the obtuse edge produced by the two faces of cleavage M and 7*, which he gives = 95° 2(X, is replaced by a face inclined at angles of 139° 45' on T, and of 135° 30' on M. P is inclined on M at an angle of 126°, a face replacing the obtuse edge between P and Jl/, on P at an angle of 156° 30', and another which replaces the acute edge between P and the opposite face of M, is inclined towards P at an angle of 94° 15'. H. 28S PHYSIOGRAPHY. CLASS II. been analysed by STROMEYER, another from Finland by ROSE ; they have yielded the following results : Silica 51-445 51-60. Lime 47-412 46.41. Protoxide of Iron 0-401 a trace. Oxide of Manganese 0-257 0-00. Water and loss by heating 0-076 0-00. Mechanical admixtures 0-00 I'll. Its chemical formula Ca3 Si > agrees with 47'24 lime and 52*76 silica. Before the blowpipe it melts on the edges into a semi-transparent colourless enamel. It requires a strong heat for melting, and sometimes boils a little. It is easily dissolved by borax, and in considerable quantity, and forms with it a transparent globule. By fusing lime and silica in the required proportions, cleavable masses of the present species have been obtained, but not yet any crystals. 2. The oldest variety known of prismatic Augite-spar is from Cziklowa near Orawitza, in the Bannat of Temeswar, where it occurs in several copper mines. It is associated with several ores of copper, also with rhombohedral Lime- haloide, with pyramidal Kouphone-spar, &c. In Finland it occurs in limestone, at Edinburgh, in the greenstone of the Castle-hill; it is also found in several localities in America, and with Essonite in Ceylon. The variety from Capo di Bove near Home, first called Wollastonite, but now supposed to be perhaps different from the present species, occurs in lava resembling basalt, and is associated with paratomous Augite-spar, trapezoidal Kouphone- spar, &c. GENUS IX. AZURE-SPAR. 1. DODECAHEDHAL AZUEE-SPAR. Azurestone or Lapis Lazuli. JAM. Syst. Vol. I. p. 39!). Man. p. 317. Lapis Lazuli. PHIL L. p. 44. Lasur- stein. WERN. Hoffm. H. B. II. 1. S. 276. Lasur- OP.DEH VI. DODECAHEDRAL AZURE -SPAR* 289 stein. HAUSM. II. S. 543. Lasurstein. LEONH. S. «50. Lezulite. HAUY. Traite,T. III. p. 145. Tabl. comp. p. 47. Traite, 2de Ed. T. III. p. 54. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple form. D. Vol. I. Fig. 31. Cleavage, dodecahedron imperfect. Fracture im- perfect conchoidal, uneven. Surface even, though rough. Lustre vitreous. Colour various shades of azure- blue. Streak blue, paler than the colour. Trans- lucent, generally only on the edges. Brittle. Hardness = 5-5 ... 6-0. Sp. Gr. =2-959, KARST^N; = 2-3 ... 2-4, BREITHAUPT. Compound Varieties. Massive: composition granular, individuals strongly connected ; fracture uneven. OBSERVATIONS. 1. The difference in the two preceding statements of the specific gravity shews that the present place of the species cannot yet be considered as definitively settled. 2. Dodecahedral Azure-spar consists, according to GME- LIN, of Silica 49-00. Magnesia 2-00. Alumina 11-00. Lime 16-00. Potash and Soda 8-00. Oxide of Iron 4-00. Sulphuric Acid 2-00., with a trace of water and hydro-sulphuric acid. Be- fore the blowpipe it melts with difficulty into a glassy globule, which is first of a blueish tinge, but soon becomes VOL II. T 290 PHYSIOGRAPHY. CLASS II. white. The compact varieties melt more easily and with a slight effervescence. It is dissolved with considerable effervescence by borax, and forms with it a clear globule. If previously burnt and reduced to powder, it loses its co- lour and forms a jelly with acids. 3. Nothing is known with certainty in regard to the geological rektions of the present species. From its mix- ture with limestone, it seems to be found originally in beds. But it is also said to have been found in veins travers- ing primitive rocks. It is generally associated with hexa- hedral Iron-pyrites. 4. Dodecahedral Azure-spar has been long ago brought from Lesser Bucharia, Thibet, and China. It has been lately found at Lake Baikal in Siberia, as it is said, in veins with hexahedral Iron-pyrites, prismatic Feld-spar, and do- decahedral Garnet. 5. Ultramarine is obtained from it. It is also cut into various ornamental articles, as ringstones, snuff-boxes, &c. 2. PRISMATIC AZURE-SPAR. Prismatic Azure-spar, first subsp. JAM. Syst. Vol. I. p. 392. Prismatic Azure-spar. Man. p. 180. Lazulite. Azurite. PHILL. p. 94. Lazulit. WERN. Hoffm. H. B. II. 1. S. 285. Korniger Lazulith. HAUSM. II. S. 372. Lazulith (in part). LEONH. S. 415. Lasulit de Werner. HAUY. Tabl. comp. p. 62. Lazulite. Traite', 2de Ed. T. III. p. 54. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Simple forms. |P — 2 ? ; f P — 2 ? ; P ; P +jx = 91° 30' ; Pr = 58°30'; Pr = 59°20'. Char, of Comb. Prismatic. The crystals of this mi- neral possess in general a great deal of resem- blance with those of prismatic Sulphur. As in ORDER vi. PRISMATIC AZURE-SPAR. 9QI the latter, P is an acute pyramid. Lateral edge = 136° 20'.* Cleavage, P -f- oo indistinct. „ Fracture uneven, Surface smooth, all the faces alike. Lustre vitreous. Colour various shades of a pure blue colour, particularly deep and beautiful, if viewed in the direction of one line, apparently the axis of the crystals, while perpendicular to it, it is of a pale greenish-blue colour. Streak white. Translucent, generally only on the edges, opake. Brittle. Hardness = 5-0... 5-5. Sp. Gr. = 3-056. Compound Varieties. Massive : composition gra- nular, individuals strongly connected. OBSERVATIONS. 1. According to FUCHS, the prismatic Azure-spar from the Radelgraben in Salzburg consists of Phosphoric Acid 41-81. Alumina 3573. Magnesia 9-34. Silica 2-10. Protoxide of Iron 2'64. Water 6-06. Before the blowpipe it intumesces a little, and assumes a glassy appearance, where the heat has been highest, but does not melt. With borax it yields a clear colourless glo- bule. Treated with boracic acid, and a piece of iron-wire, it gives a globule of phosphuret of iron. 2. It has been found in narrow veins, traversing clay, slate, both massive and crystallised, with rhombohedral " The angles are given according to BROOKE and PHIL- UPS. H. PHYSIOGRAPHY. CLASS n. Quartz and brachytypous Parachrose-baryte. It occurs near Werfen in Salzburg, in the valleys called Schlamming and Radelgraben. Whether or not the Lazuhte from Waldbach in the district of Vorau in Stiria, and from the Rathhausberg in Salzburg, belong to the present species, is yet to be ascertained. 3. PRISMATOIDAL AZURE-SPAR. Prismatoidal Azure-spar or Blue Spar. JAM. Syst. Vol. I. p. 306. Man. p. 180. Blue Felspar. PHILL. p. 115. Blauspath. WERN. Hoffm. H. B. II. 1. S. 287. Split- triger Lazulith. HAUSM. II. S. 373. Lazulith (in part). LEONH. S. 415. Feld-Spath bleu. HAUY. Trait^, T. II. p. 605. Tabl. comp. p. 60. Traite', 2de Ed. T. IV. p. 490. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Simple forms and combinations unknown. Cleavage, indistinct, sometimes pretty easily ob- served in only one direction. Also traces in other directions making oblique angles with the former. Fracture uneven. Lustre vitreous, slightly inclining to pearly upon faces of cleavage. Colour smalt-blue, inclining sometimes to white or green. Streak white. Translucent on the edges, often nearly opake. Brittle. Hardness = 5«5 ... 6-0. Sp. Gr. = 3-024, the Stirian variety. Compound Varieties. Massive: composition granular, often in large individuals ; strongly co- herent. Fracture often splintery. 1. So little is known of the geometrical properties of the ORDER VII. PRISMATIC ANDALUSITE. £93 present species, that it is impossible to say whether it is really different from the preceding one, since the characters taken from hardness and specific gravity, and others very nearly agree. The chemical composition has been found to be almost exactly the same. R. BHANDES obtained Phosphoric Acid 43-32. Silica 6*50. Alumina 34*50. Magnesia 13-56. Lime 0-48. Protoxide of Iron 0-80. Water 0-50. Before the blowpipe it loses its colour, but does not melt. It is slowly and difficultly dissolved in borax. With bora- cic acid and iron-wire it yields a globule of phosphuret of iron. 2. Prismatoidal Azure-spar occurs in masses, sometimes pretty considerable, also in large indistinct crystals im- bedded in rhombohedral Quartz, and mixed with Mica. It has not been found in its original repositories, which seem to be beds. 3. It occurs in the valley of Freschnitz near Krieglach on the Miirz in Upper Stiria. Boulders of the rock con- taining the blue mineral are found also at Therenberg on the foot of the Wechsel mountain in Lower Austria. II. GEM. GENUS I. ANDALUSITE. 1. PRISMATIC ANDALUSITE. Prismatic Andalusite, first subsp. JAM. Syst Vol. I. p. 68. Man. p. 181. Andalusite. PHILL. p. 108. An- dalusit. WERN. Hoffm. H. B. II. 1. S. 291. Anda- lusit. HAUSM. II. S. 506. Andalusit. LEONH. S. 475. Feld-Spath apyre. HAUY. Traite', T. IV. p. 362. Tabl. comp. p. 60. Trait^, 2de Ed. T. IV. p. 486, 294 PHYSIOGRAPHY. CLASS n. Fundamental form. Scalene four-sided pyramid. P = 120° 27', 118° 39', 90° 47'. Vol. I. Fig. 9. LEONHARD. Simple forms. P — QD (P) ; P + QD (M ) = 91° 33'; ?r(0 = 109°28'; Pr = 108°0'; Pr+x. Char of Comb. Prismatic. Combinations. 1. P — oo. P + OD. 2. ?r. P -f oo. 3. P — QD. Pr. P 4- oo. Fig. 3. All of them from Lisenz, Tyrol. Cleavage. P + QD very distinct, often covered with scales of mica ; Pr -f- QD more smooth and shining, but interrupted and less easily obtain- ed. Traces of Pr, and Pr + OD, the latter scarcely perceptible. Fracture uneven. Surface, uneven and rough, seldom smooth. Generally covered with plates of mica. Lustre vitreous. Colour flesh- red, passing into pearl-grey. Streak white. Translucent on the edges. Hardness — 7-5. Sp. Gr. = 3-104 of a cleavable variety. Compound Varieties. Massive : composition indistinctly granular and columnar. OBSERVATIONS. 1. Among the minerals which accompany the prismatic Andalusite from the Tyrol, there is one which possesses its form, but none of its other properties. Its hardness is ss 5-0, the specific gravity = 3-543 ; besides, the crystals are compound, and seem to be pseud omorphic, perhaps be- ORDER vii. DODECAHEDRAL CORUNDUM. 295 longing to the species of prismatic Disthene-spar. It has often been erroneously considered as grey Andalusite. 2. According to BUCHOLZ, the prismatic Andalusite con- sists of Alumina 60-5. Silica 36-5. Oxide of Iron 4*0. Before the blowpipe it is infusible, even in thin splinters or in powder, but it becomes covered with white spots. It is difficultly soluble in borax, even when reduced to powder, and almost only on the edges in salt of phos- phorus. 3. Crystals of prismatic Andalusite are found imbedded in mica slate, or implanted in the cavities of rocks, forming irregular beds or nodules in granite and primitive slate. It is generally associated with rhombohedral Quartz, some- times with Finite. 4. This species was first discovered in the province of Andalusia in Spain, from whence it has been called Anda- lusite. Varieties of it have been afterwards found near Braunsdorf in Saxony, at Herzogau in the Upper Pala- tine, in several places in France, and at Kaplitz on the frontiers of Austria and Bohemia. Crystals of very consi- derable magnitude are found in the valley of Lisenz near Inspruck in the Tyrol. GENUS II. CORUNDUM. 1. DODECAHEDBAL CORUNDUM. Octahedral Corundum, second and third subsp. JAM. Syst. Vol. I. p. 41. 43. Dodecahedral Corundum. Man. p. 182. Spinelle Ruby. Pleonaste. PHILL. p. 90. 92. Spinel (with exception of Salamstein). Zeilanit. WEEN. HofFm. H. B. I. S. 530. 535. Spinell. Pleonast. HAUSM. II. S. 360. 363. Spinell. LEONH. S. 511. Spinelle. Ple'onaste. HAUY. Traite', T. II. p. 496. T. III. p. 17- Tabl. comp. p. 31. Alumine magnesiee on Spinelle (with exception of Sp. zincifere). Traite, 2de Ed. T. II. p. 166. 296 PHYSIOGRAPHY. CLASS n. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. 6 (P). Vol. I. Fig. 2. ; I) (o). Vol. I. Fig. 31. C2 (r). Vol. I. Fig. 34. Char, of Comb. Tessular. Combinations 1. O. D. %>. O. D. Cs. Irregular forms, grains. Cleavage, octahedron difficult. Fracture conchoi- dal. Surface smooth, the icositetrahedron some- times striated parallel to the edges of combina- tion with the octahedron. Lustre vitreous. Colour red, passing into blue and green, also into yellow, brown, and black. Sometimes nearly white. Streak white. Trans- parent ... translucent, only on the edges if the colour be very dark. Hardness = 8-0. Sp. Gr. = 3-523, of a transpa- rent variety, between cochineal- and carmine-red. Compound Varieties. Twin-crystals, face of com- position parallel, axis of revolution perpendicular to a face of the octahedron. Fig. 156. Sometimes parallel to several faces of the octahedron. OBSERVATIONS. 1. The varieties called Salamstcin by WERNER cannot be received in the species of dodecahedral Corundum, as their forms belong to the rhombohedral system, but it is necessary to include in it the varieties called Zeilanite or Pleonastc, which differ only in regard to colour, and perhaps to specific gravity, owing to an admixture of oxide of iron. 2. The contents .of three varieties of dodecahedral Co- rundum have been found as follows : Blue Spinelle Red Spindle. Pkonaste from Aker. from Ceylon. Alumina 72-25 74'50 68-QO, ORDEaVIl. DODECAIIEDUAL CORUNDUM. 297 Silica 6-45 15-50 2-00. Magnesia 14-63 8-25 12-00. Oxide of Iron 4-26 1-50 16-00. Lime 0-00 BERZ. 0*75 KLAPR. 0-00. DESCOT. VAUQUELiy discovered 6-18 per cent, of chromic acid in the red Spinelle. The pure varieties are designated by BERZELIUS with Mg Al4, corresponding to 83-25 of alu- mina and 16-75 of magnesia. Pleonaste contains, besides, a proportion of oxide of iron. The red varieties, exposed to heat, become black and opake ; on cooling, they appear first green, then almost colourless, and at last re-assume their red colour. They are difficultly fusible with borax, a little more easily with salt of phosphorus. Pleonaste yields a deep green globule. Dodecahedral Corundum assumes positive electricity by friction. 3. The original repositories of several varieties of the present species are certainly rocks or mountain masses ; but it is not known with certainty whether this be everywhere gneiss, as it has been quoted for several localities. Crys- tals from Ceylon have been observed imbedded in lime- sto«e, mixed with mica, or in rocks containing adularia, which seem to have belonged to primitive rocks. Other va- rieties, commonly called Pleonaste, occur in the drusy ca- vities of rocks ejected by Vesuvius. The greater part, however, of the varieties of dodecahedral Corundum are found in more recent deposits, formed by diluvial or allu- vial action, along with crystals of rhombohedral Corundum, pyramidal Zircon, and other gems, also with octahedral Iron-ore. 4. Dodecahedral Corundum is principally brought from Ceylon, where it occurs in isolated crystals in the sand, or also imbedded in gneiss. All the regular forms mentioned above, have been observed in this variety. In Sudermanland in Sweden, blueish and pearl-grey varieties occur imbedded in granular limestone. Pleonaste occurs in Ceylon in sand, and in implanted crystals in Vesuvius. 5. Clear and finely coloured red varieties of the present 298 PHYSIOGRAPHY. CLASS 11. species are highly prized as ornamental stones. They go generally by the name of Spindle lluhy, or Balas Ruby. %. OCTAHEDRAL CORUNDUM. Octahedral Corundum, first subsp. JAM. Syst. Vol. I. p. 39. Octahedral Corundum or Automalite. Man. p. 184. Automalite. PHILL. p. 83. Automolit. WERN. Hoffm. H. B. I. S. 526. Gahnit. HAUSM. II. S. 364. Gahnit. LEONH. S. 513. Spinelle zincifere. HAUY. Tabl. comp. p. 67. Traite^ 2de Ed. T. II. p. 170. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple form. 6 (P). Vol. I. Fig. 2. Cleavage, octahedron, perfect. Fracture conchoi- dal. Surface rough, sometimes covered with mi- ca, or with dodecahedral Garnet-blende. Lustre vitreous, inclining to resinous. Colour dirty green tinges, inclining to black and blue. Streak white. Translucent on the edges ... nearly opake. Hardness = 8-0. Sp. Gr. — 4-232. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendi- cular to a face of the octahedron. Fig. 156. OBSERVATIONS. 1. Octahedral Corundum consists, according to ECKE- BERG, Of Alumina 60-00. Oxide of Zinc 24-25. Oxide of Iron 9-25. Silica 4-75. with a trace of oxide of manganese and lime. The pure mixture is considered by BERZELIUS to be expressed by ORDER VII. EHOMBOHEDEAL CORUNDUM. 299 Zn Al4, which corresponds to 71'86 of alumina, and 28-14 oxide of zinc, not giving attention to the contents of oxide of iron and silica. Alone it is infusible before the blowpipe, and nearly so with borax or salt of phospho- rus. With soda it melts imperfectly into a dark scoria, which being melted again with soda, deposits upon the charcoal an areola of oxide of zinc. 2. The varieties of the present species generally occur imbedded in talcose slate and quartz, and accompanied with hexahedral Lead-glance and dodecahedral Garnet-blende ; sometimes also with prismatic Gadolinite, dodecahedral Garnet, &c. It is found at Fahlun and Broddbo in Swe- den, and in the vicinity of the Franklin iron-works in New Jersey. 3. EHOMBOHEDEAL COEUNDUM. Rhomboidal Corundum. JAM. Syst. Vol. I. p. 48. Man. p. 148. Corundum. PHILL. p. 74. Saphir. Salamstein. Sclimirgel. Korund. Demantspath. AVERN. Hoffm. H. B. I. S. 541. 547. 561. 565. 572- Korund. HAUSM. II. S. 366. Korund. LEONH. S. 393. Tele'sie. Corindon. HAUY. Traite, T. II. p. 480. T. III. p. 1. Corindon. Tabl. comp. p. 29. Traitd, 2de Ed. T. II. p. 70. Fundamental form. Rhombohedron. R = 86° 6'. R. G. a = V 5-5609. Simple forms. R — oc (o) ; R (P) ; R + 1 (a) = 68° 45'; P + 1 (r) = 128° 3', 122° 18'; P + 8 (b) = 122° 2%, 149° 1% ; P + 3 (e) = 120° 37, 164° 2(X ; f P + 1 = 136° 47', 94° 53' ; J P + 1 (c) = 126° 16', 129° 5% ; f P + 2 = 124° 1', 139° 40' ; | P + 3 (I) = 121° 5', 159° IV; |P + 4 = 120°17/,169°30'; R + oc; 300 PHYSIOGRAPHY. ClASS II. P H- oo (s) ; (P 4- oo)5 = 133° 1(X 25", 166° 49' 35". Char, of Comb. Rhombohedral. Combinations. 1. R — QD. R. Sim. Fig. 111. Gellivara, Sweden. 2. R — oo. P -f GO. Malabar. 3. R — GO. R. P-hx. Ceylon. 4. R— oo. R. P + l. P-f oo. Fig. 121. Ceylon. 5. P+l. R+ 1. P + 2. P+ oo. Fig. 122. Ceylon. 6. R — oo. ^P-f-1. |P + 3. P + 3. P+o>. Fig. 123. Ceylon. Irregular forms, grains. Cleavage, R — CD in some varieties perfect, but in- terrupted by conchoidal fracture. The faces ob- tained in the direction of the rhombohedron R, almost always originate in composition. The faces of cleavage and regular composition are striated parallel to their common edges of in- tersection. Fracture conchoidal, uneven. Sur- face, R — CD striated parallel to the edges of combination with R ; sometimes also P -f oo in the same direction. The isosceles pyramids and generally also P -|- oo are often deeply striated in a horizontal direction. Lustre vitreous, much inclining in some varieties to pearly upon R — QD. Colour blue, red, green, yellow, brown, grey, and white. Some of the blue, red, and yellow colours, very lively and beautiful. Streak white. Transparent ... translucent. In several varieties, if cut round, ORDER VII. RHOMBOHEDRAL CORUNDUM. 301 a six-sided opalescent star is observable in the direction of the axis. Hardness = 9-0. Sp. Gr. = 3-979, blue, transparent (Sapphire). 3-949, green, translucent (Corundum). 3-921, brown, faintly translucent (Ada- mantine-spar). 3-909, red, transparent (Ruby). Compound Varieties. Regular composition pa- rallel to one or more of the faces of R, repeated in parallel layers, very frequent. Massive : composi- tion granular, often impalpable, and then the frac- ture becomes splintery and uneven. OBSERVATIONS. 1. Among the varieties of rhombohedral Corundum, four species used formerly to be distinguished, for the greater part easily ascertained, but also united by such varieties as possess intermediate properties between them, and produce continuous transitions. By these transitions, how- ever, also the Salamstone is included, which "WERNER. considered as a sub-species of Spinelle, and which consists of small transparent crystals, generally six-sided prisms, of pale reddish and blueish colours. Most of the transparent simple varieties, however, were designated by the name of Sapphire, while the compound ones were called Emery. The varieties of Sapphire generally possess an indistinct cleavage and a conchoidal fracture; the surface of its crystals is smooth, though not always even. The re- maining varieties differ almost only in colour, Corundum9- • The corundum of Battagammana is frequently found in large six-sided prisms; it is commonly of a brown colour, whence it is called by the natives " Curundu galle," cinnamon- 302 PHYSIOGRAPHY. CLASS II. stone comprehending those whose colour is green, blue, or red, and in most cases inclining to grey, while those of Adamantine -spar are hair-brown and reddish-brown. Both of them are easily cleavable, or at least shew faces of com- position parallel to the fundamental rhombohedron, and the crystals possess a rough and uneven surface. There are many crystals, part of which is Sapphire, and part Ada- mantine-spar. 3. The following ingredients have been found in rhom- bohedral Corundum : Sapphire. Corundum-stone, Emery. Alumina 98-50 89-50 86-00. Silica 0-00 5-50 3-00. Oxide of Iron 1-00 1-25 4-00. Lime 0-50 KLAPR. 0-00 KLAPR. 0-00. TENNANT. Its chemical formula is Al, expressing 53-29 of aluminium, and 46-71 of oxygen. Before the blowpipe it is infusible whether alone or with soda ; it is difficultly but entirely dis- solved in borax, and if previously reduced to powder, also in salt of phosphorus. It is not acted upon by acids. 3. Rhombohedral Corundum is found in imbedded crys- tals and in massive varieties. The first of them, and par- ticularly Sapphire and Salamstone, are chiefly met with in se- condary repositories, as in the sand of rivers, &c. and is ac- companied by crystals and grains of octahedral Iron-ore, and of several species of gems. Corundum-stone is found in imbedded crystals in a rock, which consists, according to Count BOURNON, of Indianite, and contains Felspar, Fib- rolite, several species of Augite-spar and Gem, and also octahedral Iron-ore. Adamantine-spar occurs with octahe- dral Iron-ore and Fibrolite in a sort of granite, containing no quartz. The varieties from Piedmont are imbedded in stone. Dr J. DAVY'S Account of the Interior of Ceylon, p. 25. Dr DAVY adds, that the corundum and sapphire are so closely allied, that even the natives of Ceylon have not failed to observe the connexion, H. ORDER vu. EHOMBOHEDEAL CORUNDUM. 303 compact Felspar. Some varieties have been discovered imbedded in octahedral Iron-ore and macrotypous Lime- haloide, and seem to occur in beds. Those compound va- rieties of which the original repository has been ascertain, ed, occur in a bed of talcose slate, contained in mica-slate. 4. The finest varieties of Sapphire come from Pegu, where they occur in the Capelan mountains near Syrian. Some have also been found at Hohenstein in Saxony, at Bi- lin in Bohemia, at I*uy in France, and in several other coun- tries. Corundum occurs in the Carnatic in the East Indies ; Adamantine-spar in the neighbourhood of Canton in China and the coast of Malabar. In St Gothard red and blue va- rieties of the present species occur in Dolomite. Those from Gellivara in Sweden, imbedded in octahedral Iron- ore, are of a yellowish-white colour. Emery is found in the higher part of Saxony, in the mountain called Ochsenkopf near Schneeberg, and is of a dark blue colour, inclining to grey ; it approaches to the appearance of blue Corundum, whenever its individuals are of considerable size. In the island of NaxosT and several other islands of the Greek ar- chipelago, also at Smyrna, Emery is found in large boul- ders on the surface of the earth mixed with other minerals. 5. The pure and transparent varieties of rhombohedral Corundum, if finely coloured, are in great estimation as orna- mental stones. The red varieties are most highly valued, and go by the name of Oriental Ruby, the violet-blue are called oriental Amethyste, the green oriental Emerald, the yellow oriental Topaz, and the blue oriental Sapphire. As- teriais a variety of Sapphire, not perfectly transparent, and shewing a starlike opalescence in the direction of the axis if cut round. Much use is made of Corundum and Ada- mantine-spar, particularly in India and China, for cutting and polishing steel and gems, and it is said even of dia- mond, ^which has given occasion to the name of Ada- mantine-spar. Yet they are much inferior in this respect to the powder of diamond ; and European artists therefore make use of the latter for cutting the diamond, and for ex- 301 PHYSIOGBArHT. CI.ASS u. editing fine works in other hard stones. Emery yields a well known grinding material. 4. PRISMATIC CORUNDUM. Prismatic Corundum or Crysoberyl. JAM. Syst. Vol. I. p. 64. Man. p. 180. Chrysoberyl. PHILL. p. 89. Krisoberil. WERN. Hoffm. H. 15. I. S. 424. Chryso- beryll. HAUSM. II. S. 385. Chrysoberyll. LEONH. S. 437. Cymophane. "HAUY. Traite', T. II. p. 491. Tabl. comp. p. 30. Traite^, 2de Ed. T. II. p. 303. Fundamental form. Scalene four-sided pyramid. I1 = 139° 53', 86° 16', 107° 29'. Vol. I. Fig. 9. R. G. a i b : c = 1 : V 2-9731 : J 0-6567. Simple forms. P (o) ; P + QD = 128° 35'; (P)3 (n) ; (P + oo)* CO = 70° 41' ; (Pr + oo)' (*) = 93° 33' ; ?r (i) - 119° 46' ; ?r + oo (T) ; Pr -f OD (M). Char, of Comb. Prismatic. Combinations. l.?r. Pr-f oo. Pr+ QD. Haddam, Connecticut. 2. Pr. (Pr+oc)3. Pr-f- oo. Pr+ oo. Haddam. 3. Pr. P. (f + Go)3. Pr+ a. Pr-f- GD. Fig.25. Siberia. 4. ?r. P. (?)*. (P-foo)3. Pr-f oo. Pr+ oo. Brazil. Irregular forms, grains, pebbles. Cleavage, Pr -f co and Pr -f- oo, not very distinct, the first a little more easily obtained. Faint traces parallel to P — QD. Fracture conchoidal. Surface, the vertical planes, and particularly Pr -|- oo, striated parallel to their common edges ORDER VII. PRISMATIC COKUNDUM. 305 of intersection. The rest generally smooth and even, Pr sometimes a little rough. Lustre vitreous. Colour asparagus-green, pass- ing into greenish-white, olive-green and yellow- ish-grey. Streak white. Transparent ... trans- lucent. Blueish opalescence upon Pr and Pr -f- GO, or in general if viewed in a direction perpendicular to the short diagonal of the fundamental form. Hardness = 8-5. Sp. Gr. = 3-754, a transparent asparagus-green variety. Compound Varieties. Twin-crystals : face of composition perpendicular, axis of revolution par- allel to one of the acute terminal edges of P. The composition is frequently repeated on all the simi- lar terminal edges, nearly as in Fig. 38., and easily ascertained by the striae on the faces of Pr + oo, which fall into one plane. The composition is very common in the present species. OBSERVATIONS. 1. According to SEYBERT, who analysed two varieties, one from Brazil, and another from Haddarn, it consists of Alumina 68-666 Glucina 16-000 Silica 5-999 Protoxide of Iron 4«733 Oxide of Titanium 2-666 Moisture 0-666 73-60. 15-80. 4-00. 3-38. 1-00. 0-40. It remains unchanged if exposed alone or with soda to the heat of the blowpipe, only the surface in the latter case be- comes dull. It is difficultly, but perfectly fusible with borax and salt of phosphorus. 2. Also in this species the original repositories of some VOL. II. U 306 PHYSIOGRAPHY. CLASS n. varieties are not known, having been found only in the alluvial deposits of rivers along with other species of gems. Thus it occurs in Brazil, along with octahedral Dia- mond and prismatic Topaz ; also in Ceylon. Near Had- dam in Connecticut and Saratoga in New York, it occurs in a kind of granite, imbedded in Albite and rhombohedral Quartz, and associated with dodeeahedral Garnet, rhombo- hedral Emerald, rhombohedral Tourmaline, and prismatic Tantalum-ore. The original matrix of the large Siberian crystals is not known. GENUS III. DIAMOND. 1. OCTAHEDRAL DIAMOND. Octahedral or Common Diamond. JAM. Syst. Vol. I. p. 1. Octahedral Diamond. Man. p. 187. Diamond. PHILL. p. 361. Demant. WERN. Hoffm. H. B. I. S. 358. Demant. HAUSM. I. S. 59. Diamant. LEONH. S. 115. Diamant. HAUY. Traite, T. III. p. 287. Tabl. comp. p. 60. Traite', 2de Ed. T. IV. p. 419. Fundamental form. Hexahedron. Vol. 1. Fig. 1. Simple forms. H ; 6. Vol. I. Fig. 2. ; D. Vol. I. Fig. 81. ; T. Vol. I. Fig. 35. Char of Comb. Tessular. Combinations. 1. H. D. Fig. 151. 2. O. D. 3. O. T. 4. O. D. T. All of them from Brazil. Irregular forms, grains. Cleavage, octahedron, highly perfect. Fracture conchoidal. Surface, the octahedron sometimes faintly streaked parallel to its edges of combina- tion, but in general very smooth. Also the do- decahedron if often streaked, rough, and uneven, the tetraconta-octahedron curved, and smooth. Grains possess a rough and granulated surface. oaDEn vir. OCTAHEDRAL DIAMOND. 307 Lustre, bright adamantine. Colour white, preva- lent. Also various shades of blue, red, yel- low, green, brown, grey, and even black. Ge- nerally pale. Streak white. Transparent ... translucent, dark coloured varieties only on their edges. If cut and polished, it shews a most lively play of colour. Hardness = 10-0. Sp. Gr. = 3-520 of a white va- riety. Compound Varieties. Twin-crystals. 1. Face of composition parallel, axis of revolution perpen- dicular to a face of the octahedron. Fig. 156. 163. 2. Face of composition parallel, axis of revolution perpendicular to a face of the hexahedron. The individuals, having the general aspect of tetrahe- drons, are continued beyond the face of composition. OBSERVATIONS. 1. Many of the combinations occurring in the present species, possess a semi-tessular character. There occur also simple forms, which present the same peculiarity, as, for instance, the icositetrahedron, VoL I. Fig. 25. and Fig. 26. Twin-crystals, like Fig. 164,* are possible only upon, the supposition of semi-tessular forms. They have been first described in the Catalogue of the collection of Mr VON DER NULL. It will depend upon future observation, whether this character is general in the present species. 2. Octahedral Diamond is perfectly combustible at a tern- * This figure represents a very distinct crystal in the collec- tion of Mr ALLAN. Similar varieties have been observed, and models illustrative of their formation, are exhibited in the British Museum. H. 308 PHYSIOGRAPHY. CLASS n. perature of about 14° wedg and yields with oxygen, car- bonic acid gas. It is not acted upon by acids or alcalis. 3. The rocks hitherto considered as the matrix of octahe- dral Diamond, are secondary ones, as several kinds of sand- stone, consisting of aggregated quartz-pebbles. Octahedral Diamond is also found in strata of ironshot sand and clay, and in the loose sand of plains and rivers. In a speci- men from Brazil, in the possession of Mr HEULAND, it is associated with Skorodite, and imbedded in a compact vanety of prismatic Iron-ore. 4. The octahedral Diamond was first discovered in the East Indies, where it has been worked for many centu- ries, and in Brazil. They are found in various places on the eastern coast of the British peninsula in India, but parti- cularly between Golconda and Masulipatam, also near Pan- na in Bundelcurid. There occur some likewise in the pe- ninsula of Malacca, and the isle of Borneo. In Brazil they occur in the district of Serro do Frio in the capitania of Minas Geraes, and were first discovered in the Riacho Fundo, then in llio do Peixe, and also in the Terra de St Antonio. 5. Octahedral Diamond is the most valued of all the gems, and is used as an ornamental stone. But it is em- ployed likewise for cutting glass, and for engraving, cutting and polishing other hard stones and the octahedral Diamond itself. GENUS IV. TOPAZ. 1. PRISMATIC TOPAZ.- Prismatic Topaz. JAM. Syst. Vol. I. p. 78. Man. p. 188. Topaz. PHILL. p. 84. Topas. Phisalit. Picnit, cder Schorlartiger Beril. WERN. Hoffm. H. B. I. S. 577- 620. IV. 114. Topas. HAUSM. II. S. C48. Topas. LEONH. S. 405. Topaze. Pycnite. HATJY. Traite, T. II. p. 504. T. III. p. 236. Silice fluatee alumineuse. . Topaze. Tabl. camp. p. 17- Alumine fluate'e siliceuse ou Topaze. Traite', 2de Ed. T. II. p. 131. ORDEtt VII PRISMATIC TOPAZ. 309 MONTEIRO. Denkschr. der Akad. der Wissensch. zu Munchen. Jahr 1811 and 1812. S. 223. Fundamental form. Scalene four-sided pyramid. P = 141° 7, 101° 52', 90° 55'. Vol. I. Fig. 9. R. G. a : b : c = 1 : V 4-440 : V 1-238. Simple forms. P — oo (P) ; P — 1 = 155° 37', 122° 39', 53° 5%' ; | P — 1 (s) = 149° 38', 120° 32', 68° 14' ; P (o) ; P + 1 = 130° 27', 74° 39', 127° 36'; P+ oo (M ) = 124° 19'; (4 pr _ i)5 (^ _ 123o V9 126o 18/5 82o 8/ . (?r + QD)3 (0 = 86° 52'; (Pr + oo)5 = 103° .14'; (P + oo)5 = 64° 31' ; Pr + 1 (ri) = 92° 59; Pr + 2 (y) = 55° 34'; Pr + QD (r) ; Pr + 1 (e) = 58° 11' ; Pr + QD = (/). Char, of Comb. Prismatic. Some of the crystals shew different faces on opposite ends. Combinations. 1. P. P + oo. (Pr + oc)5. Brazil. 2. P. Pr-j-1. P+oo. (Pr+oo)3. Nert- schinsk, Siberia. 3. P. Pr+1. Pr+1. P + oo. (Pr+c/>)3. Peru. 4. P— 1. |P — 1. (|Pr — I)3. P. Pr+1. P + oo. (Pr + a)3. Mucla, Asia Minor. 5. P — oo. I P — 1. (|Pr— I)3. P. Pr+1. Pr + 2. P + x. (Pr + oo)3. Fig. 34. Schneckenstein, Saxony. 6. (I Pr— I)3. P. Pr + 1. P+oo. (?r + oo)3. Pr+1. P. Fig. 36. Brazil. Cleavage. P — QD highly perfect ; ?r + 1 and Pr + 1 imperfect. Traces of P + oo and (Pr + oo)5 par- 310 PHYSIOGRAPHY. CLASS u. ticularly in the Scottish varieties. Fracture more or less perfectly small conch oidal, uneven. Sur- face, P — oo rough, sometimes faintly striated parallel to the edges of combination with (Pr -f oo)5. The vertical prisms always striated, sometimes deeply, parallel to their common edges of combination. The pyramids and horizontal prisms smooth. Lustre vitreous. Colour, white, yellow, green, blue. Various, but generally pale shades. Streak white. Transparent ... translucent, sometimes only on the edges. Hardness = 8-0. Sp. Gr. = 3-499 of a transpa- rent crystallised variety ; = 3*494, of the colum- nar compositions of Pycnite. Compound Varieties. Massive: composition gra- nular, of various sizes of individuals ; faces of com- position rough. There occurs also columnar com- position, the individuals being thin, long and paral- lel, and easily separated, and their faces of compo- sition longitudinally streaked. OBSERVATIONS. 1. However easily the different varieties of prismatic Topaz may be found out and distinguished from the rest of minerals, if we attend to their characteristic properties, yet this has only succeeded after several unsuccessful attempts, and even now it forms in the Wernerian system three dif- ferent species, though the varieties of rhombohedral Eme- rald, and of rhombohedral Tourmaline, which formerly were united with it, have at last been referred to their own peculiar species. Topaz contains crystalline varieties ORDER VII. PRISMATIC TOPAZ. 311 either in crystals, which are generally implanted, and have a smooth surface, or in massive granularly compound va- rieties. Here we meet with the highest degrees of trans- parency and the brightest colours. The crystals of Physa- lite are imbedded, their surface is uneven and rough ; in massive varieties they generally present large individuals, their colour inclines to a pale greenish-grey, and their trans- lucency is very faint. Pycnite has not been found in single crystals, at least not distinctly, but consists only of thin and straight columnar particles of composition, forming larger or smaller masses imbedded in other rocks, and not possessing bright colours or high degrees of transparency. The varieties of the whole species are united by transitions, and render the distinction of any one of these three kinds difficult. The optical observations, however, even in trans- parent varieties, as in those from Brazil and Scotland, in- dicate a difference between some of them which probably may lead to the establishment of several species. 2. Prismatic Topaz consists, according to BERZELIUS, of Topaz, Physalite, Pycnite, from Schneckenstein. from Finbo. from Altenberg. Alumina 57-45 6774 51-00. Silica 34-24 34-36 38-43. Fluoric Acid 7'75 7'77 8-84. In a strong heat the faces of crystallisation, but not those of cleavage, are covered with small blisters, which, however, im- mediately crack. With borax it melts slowly into a trans- parent glass. Its powder colours the tincture of violetsgreen. Those crystals which possess different faces of crystallisa- tion on opposite ends, acquire different kinds of electricity on being heated. By friction it acquires positive electri- city. 3. Prismatic Topaz enters into the composition of seve- ral granitic rocks ; thus it forms with rhombohedral Quartz and rhombohedral Tourmaline the Topaz rock of Saxony, and is found crystallised in its drusy cavities. It occurs also in irregular beds, either with quartz and mica, like the variety called Pycnite ; or with prismatic Feld-spar, rhom. PHYSIOGRAPHY. CLASS n. bohedral Quartz, rhombohedral Emerald, &c., and this is the mode in which Physalite occurs. It is found likewise in veins and beds in gneiss, mica-slate, clay-slate, and por- phyry, with pyramidal Tin-ore and prismatic Scheelium- ore, also with rhombohedral and octahedral Fluor-haloide, with rhombohedral Emerald, rhombohedral Quartz, &c. It is met with, besides, in tin stream works, and in the alluvial deposits of rivers, along with other gems. 4. Most perfect crystals of this species have been brought from Siberia, where they are found of green, blue, and white colours, along Avith rhombohedral Emerald, in the Uralian and Altai mountains, and also in Kamtschatka ; from Brazil, where they are generally met with in loose crystals and pebbles of high yellow colours ; from Mucla in Asia Minor, in pale straw-yellow, but well pronounced crystals, &c. They occur in the rock called Schnecken- stein in Saxony, of a wine-yellow colour, at Ehrenfrieders- dorf, Zinnwald, &c. along with Tin-ore, and in similar reposi- tories at Schlaggenwald in Bohemia, and St Michaelsmount in Cornwall ; with Lepidolite near Rozena in Moravia. Physalite is found at Finbo and Broddbo near Fahlun in Sweden, Pycnite at Altenberg in Saxony. In pebbles and isolated crystals, it is found in the stream-works of Euben- stock in Saxony, and in the granitic detritus at Cairngorm in Aberdeenshire, of various blueish and brownish tints, often regularly distributed in the same individual along the edges of the crystal. The varieties from the latter place are some- times beautifully crystallised. This is also the kind of re- pository in which are found the white transparent varieties of New South Wales. 5. It is used as an ornamental stone, but less valued than some of the preceding species. The blue varieties are called oriental Aquamarine by lapidaries. J[f exposed to heat, the prismatic Topaz from Saxony loses its colour, and be- comes white ; the deep yellow Brazilian varieties assume a pale pink colour, and are then sometimes mistaken for Spi- nelle or Ballas ruby. ORDER TII. PRISMATIC EMERALD. 313 GENUS V. EMERALD. 1. PRISMATIC EMERALD. Prismatic Emerald or Euclase. JAM. Syst. Vol. I. p. 89. Man. p. 190. Euclase. PHIL L. p. 101. Euklas. WERX. Hoffm. H. B. I. S. 592. Euklas. HAUSM. II. S. 654. Euklas. LEONH. S. 506. Euclase. HAU Y. Traite', T. II. p. 531. Tabl. comp. p. 32. Traite', 2de Ed. T. II. p. 528. WEISS. Verhand. der Gesellsch. nat. Freunde zu Ber- lin. 1820. S. 110. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 41. Char, of Comb. Hemi-prismatic. Cleavage, highly perfect and very easily obtained parallel to the faces T, Fig. 54., less distinct parallel to P, which is a plane replacing the edge 7c, between d' and d, and parallel also to M9 which replaces the edge e between h' and h. Fracture perfect conchoidal, and very easily obtained. Surface, the faces between T and M streaked parallel to their common intersection ; o some- times curved, the rest of the faces very smooth and shining. Lustre vitreous. Colour mountain-green, passing into blue and white, always pale. Streak white. Transparent ... semi-transparent, generally the first. Very brittle and fragile, from which property the name Euclase has been derived. Hardness = 7-5. Sp. Gr. = 3-098, a greenish-white crystal. OBSERVATIONS. 1. Prismatic Emerald, as yet a very rare mineral, has fHYSIOGllAl'IIY. CLASS II. been hitherto always found in crystals, which at first sight seem to present no difficulty to the correct developement of their simple forms. Nevertheless this has not yet been effected. The first description given by Abbe' HAUY, who determined the species, was drawn up after the crys- tal represented Fig. 54. ; but he completed what appeared to him to be wanting, and thus transformed the distinctly hemi-prismatic crystal into a prismatic one, as given in PL XLV. Fig. 52. of the first edition of his Traite. Af- • terwards the hemi-prismatic character of the combinations was established by himself in a particular memoir on the subject, and in the second edition of that work, and by Professor WEISS, but without giving more accurate mea- surements than those which had first been given by HAUY as mere approximations. The parallelism of the edges of combination between the terminal faces is not alone sufficient for their developement, without having recourse to those which they produce with the numerous prisms situated between M and T. Accord- ing to HAUY, the ratio between b and c is in the prism s = A/5 : A/ 12, in the prisms I and h it is = 2 b : 3 c and = 5 b : 12 c, the angles of the prisms = 1 14° 19'; 133° 26'; 149° 53'. A crystal in the collection of Dr ROHATSCH at Freiberg contains three prisms similarly situated, but yielding by approximate measurement, the angles of 1 14° 3G' ; 128° 39', and 144° 28'; according to the ratios of b : c ; 3 b : 4 c and b : 2 c.* Perhaps the crystal described by HAUY in fact contains other prisms ; but as the instru- ment which he made use of in his determinations is too little to be depended on, we cannot infer any thing from what has hitherto been published on the subject of the crystallisations of prismatic Emerald, but that its series of crystallisation is as yet unknown. * Mr PHILLIPS gives the angles of thirteen prisms in the same situation, whose obtuse edges are as follows: 115°4/; 117° 0'; 119° 40'; 127° 50'; 134° 20'; 136° 20'; 140° 40' ; 142° 28'; 145° 20'; 147° 16'; 149° 32'; 152° 48'; 158° 20'. H. OllDER VII. PRISMATIC EMERALD. 315 Inclination of the face*. Inclination of the edge*. df on d = 151° 46'. k on e = 130° 8'. /' On / = 106° 1 8'*. (A fragment from the Wernerian nn e> 1 2Q* Sfi' collection gave the analogous OH 6 = l^JT 00 . inclination of P on if nearly n' on » = 143° 10'f. o' on o = 112° 40^. a? (between e' and e) r' on r = 156° KX. on e = 154° 37'. z/ on u = 134° 14'§. y on e = 101° 55'. i' on i = 99° 40'||. ;r on e = 141° 4(K. The elevation of Fig. 54. is copied from the Traite of HAU Y, Fig. 154., but the projection is taken immediately from the original. The facets a, not mentioned by HAUY, follow from the situation of the edges, those between a and d being parallel to those between d and the prism /, while those be- tween a and n are parallel to those between n and «, or be- tween n and the prism s. 2. According to BERZELIUS, prismatic Emerald consists of Silica 43-22. Alumina 30-5G. Glucina 21-78. Oxide of Iron 2-22. Oxide of Tin 0-70. Before the blowpipe it intumesces in a strong heat, and becomes white. If the heat be still farther increased, it melts into a white enamel. 3. JJothing as yet is known with sufficient accuracy of the mode of its occurrence in nature. The first varieties of it were brought by DOMBEY from Peru. It has been found afterwards at Capao in the mining district of Villa- llicca in Brazil, likewise in beautiful crystallised varieties. It occurs there in a chloride slate, resting on sandstone, along with prismatic Topaz, but is generally brought to Europe in fractured crystals. * = 105° 207 and 111° 12'. f = 143° 32' and 143° 12'. = 114° 8' and 113° 407. § = 134° 20'. || == 99° 40'. = 130D 52'. According to PHILLIPS. H. 316 PHYSIOGRAPHY. CLASS u. 2. RHOMBOHEDRAL EMERALD. Rhomboidal Emerald. JAM. Syst. Vol. I. p. 92. Man. p. 191. Beryl. Aquamarine. Emerald. PHILL. p. 102. 104. Smaragd. Beril (excepting Schorlartiger Beril). WERN. Hoffm. H.B. I. S. 596. 604. Smaragd. HAUSM. II. S. 655. Smaragd. LEONH. S. 502. Emeraude. HAUY. Traite', T. II. p. 516. Tabl. coinp. p. 31. Traite, 2de Ed. T. II. p. 504. Fundamental form. Rhombohedron. II = 104° 40'. Vol. I. Fig. 7. R. G. Simple forms. R — oo (P) ; R («s) ; — R (s) ; R + oo(ra); P (0 = 151° 9', 59° 47'; P 4- 1 (M) = 135034',9802'; P + oo (M) ; (P — 2)5; (P)1 («)• Char, of Comb. Di-rhombohedral. Z (R) = 138° 4T, 89° 45r. Combinations. 1.R — oo. P-fco. Zwiesel, Bavaria. 2. R — CD. P. P + oo. Sim. Fig. 112. Siberia. 3. R — x. R -f oo. P -|- x. Schlaggenwald, Bohemia. 4. R — OD. 2 (R). P + oo. Peru. 5. R — OD. P. 2(R). P + 1. P + oo. Vol. I. Fig. 60. Peru. 6. R — oo. P. 2 (R). P + 1. 2 (R)^. P + OD. Fig. 150. Siberia. Cleavage, R — oo and P+oo, the first generally more easily obtained, the second interrupted. Fracture conchoidal, uneven. Surface^ the prisms striated parallel to the axis, seldom smooth. The rhombohedrons and pyramids smooth. P — oo ORDER VII. RHOMBOHEDllAL EMERALD. 317 sometimes rough, sometimes having a very flat six-sided pyramid upon it, the terminal edges of which are about 179° 40'. Lustre vitreous. Colour green, passing into blue, yellow, and white ; the brightest of these colours is emerald-green, the greater part of the others is pale. Streak white. Transparent ... trans- lucent. Hardness = 7-5 . . . 8-0. Sp. Gr. = 2-732 of a per- fectly emerald-green variety ; 2-678, apple- green beryl. Compound Varieties. Massive : composition ge- nerally large granular, sometimes imperfectly co- 1 umnar. OBSERVATIONS. 1. The only remarkable differences between Emerald and Beryl are in their colours, which, however, produce such an uninterrupted series, that only arbitrary limits can be fixed within it. The colour of Emerald is emerald-green ; all the varieties of other colours are Beryl. The division of the latter into precious and common Beryl depends upon the more or less perfect formation of the varieties concern- ed, particularly in regard to pureness and transparency. By divisions of this kind, however, the species becomes less interesting than it otherwise would be, on account of the great number of different varieties which it contains. 2. The analysis of a variety of Beryl from Broddbo has yielded to BERZELIUS, and that of a variety of Eme- rald from Peru to KLAPROTH, Silica 68-35 68-50. Alumina 17'60 15-75. Gluclna 13-13 12-50. Ox de of Iron 0-72 1-00. 618 PHYSIOGRAPHY". CLASS II. Oxide of Tantalum 0-27 0-00. Oxide of Chrome 0-00 0-30. Lime 0-00 0-25. In a strong heat of the blowpipe, the edges are rounded off', and a shapeless vesicular scoria is produced. Trans- parent varieties become milky. It is dissolved by borax. 3. Rhombohedral Emerald occurs in imbedded crystals in various rocks, and in implanted crystals in veins, and also in beds. It is associated with Felspar, prismatic Topaz, &c., or with pyramidal Tin-ore, and other minerals com- monly found with the latter species. It occurs also in frac- tured crystals and rolled masses in secondary repositories. 4. The finest crystals of emerald-green colours, or the real Emerald, comes from Peru, where it forms druses with rhombohedral Lime-haloide, and occurs, according to HUMBOLDT, in veins traversing hornblende slate, clay- slate, and granite. Sometimes rhombohedral Quartz and hexahedral Iron-pyrites are found along with them. Less distinct varieties, generally of muddy emerald -green colours, are found imbedded in mica-slate in the valley of Heubach, district of Pinzgau, Salzburg. The ancients procured their emeralds from Egypt. The localities however had been lost, till of very late years they have been re-discovered in Mount Zalara in Upper Egypt, where this species oc- curs in granite and mica-slate. Precious Beryl is chiefly found in Siberia and Brazil. In Siberia it occurs in the granitic district of Nertschinsk, also in the Uralian and Altai mountains, often in very large crystals, probably in veins ; in Brazil it is found in fractured crystals in the sand of rivers ; thus likewise it occurs in Aberdeenshire in Scotland, but has lately also been found engaged in the granite of Rubislaw quarry near Aberdeen. Varieties, both of precious and of common Beryl, are met with near Li- moges in France, near Zwiesel on the Rabenstein in Bava- ria, at Finbo and Broddbo near Fahlun in Sweden, in im- bedded crystals and massive varieties ; in some of the tin- mines of Saxony and Bohemia. It occurs in small quan- ORDER VII. PRISMATIC QUARTZ. 319 titles in drusy cavities of primitive rocks in various places of Salzburg; in Elba ; at Haddam in Connecticut, and other localities of America, &c. 5. Rhombohedral Emerald, when clear and transparent, is employed as an ornamental stone, and is highly valued if it is free from flaws, and possesses a fine emerald-green colour, and a certain size. Beryl is of much less value. GENUS VI. QUARTZ. 1. PRISMATIC QUARTZ. lolite. JAM. Syst. Vol. I. p. 172. Prismato Ilhomboi- dal Quartz or lolite. Man. p. 193. lolite. Dichro- ite. PHILL. p. 93. lolite. Peliom. WERN. Hoflm. H. B. I. S. 589. IV. 2. S. 11?. Dichroit. HAUSM. II. S. 659. Cordierit. LEONH. S. 420. lolithe. HAUY. Tabl. comp. p. 61. Cordierite. Traite', 2de Ed. T. III. p. 1. COEDIER. Journ. des Mines. T. XXV. p. 129. Fundamental form. Scalene four-sided pyramid of unknown dimensions. Vol. I. Fig. 9. Simple forms. P— QD; P; P + QD = 120° (nearly) ; Pr + 1 ; ?r + oo ; Pr + oo. Char, of Comb. Prismatic. Combinations. 1. P — oo. P + oo. Pr -f- x. Cabo de Gata. 2. P — oo. P. Pr + 1. P + oo. (?4-oo)5. Pr + oo. Pr + oo. Ujordlersoak, Greenland. Cleavage, P + oo and ?r -f- oo indistinct. Fracture conchoidal. Surface of some crystals rough and dull. Lustre vitreous. Colour various shades of blue, generally inclining to black. Streak while. Transparent . . . translucent ; blue if viewed in 320 PHYSIOGRAPHY. CLASS n. the direction of the axis, yellowish-grey perpen- dicular to it. Hardness = 7-0 ... 7-5. Sp. Gr. - 2-583, of a transparent variety. Compound Varieties. Massive : composition granular, strongly connected, and difficultly re- cognised. OBSERVATIONS. 1. If in the two species formerly distinguished among the varieties of prismatic Quartz, we pay no attention to their mode of occurrence and localities, no characters, how- ever accidental, remain, hy which they might be distin- guished. SteinhelUte and Hard Fahlunite likewise belong to the present species, and seem to contain varieties which will allow us some day to establish their forms with a great- er degree of precision. 2. According to STROMEYER, the present species con- sists of Silica 48-538. Alumina 31730. Magnesia 1 1 -305. Oxide of Iron 5-68G. Oxide of Manganese 0-702. Water or Loss 1-648. Before the blowpipe it melts in a good heat, but with dif- ficulty, and only on its edges, into a glass not inferior to the mineral, either in colour or transparency. 3. Prismatic Quartz occurs in aggregated crystals, with dodecahedral Garnet, rhombohedral Quartz, &c. at Cabo de Gata in Spain, in the bay of San Pedro, and these va- rieties have been called lolitc. Peliom occurs at Boden- mais in Bavaria, sometimes in very distinct crystals, but generally massive, with rhombohedral Iron-pyrites, &c. Other varieties have been found imbedded in various kinds o::i5ER VII. KHOMBOHEDRAL QUARTZ. 321 of granitic and other primitive rocks, sometimes with pris- matic Feld-spar and dodecahedral Garnet. It occurs thus in fine crystals at Ujordlersoak in Greenland, at Arendal in Norway, at Orijerfvi in Finland, in Siberia and other places. The Saplrire ffeau of jewellers is a transparent va- riety of the present species from Ceylon. 2. RHOMBOHEDJJAL QUARTZ. Rhomboidal Quartz (excepting Porcelain Jasper). Float- stone or Spongifbrm Quartz. JAM. Syst. Vol. I. p. 174. Man. p. 193. Quartz (exc. Hyalite). Cats Eye. Flint. Chalcedony (exc. Cacholong). Jasper (exc. Porcelain Jasper). Horns- one. PHH.L. p. 1. 9. 13. 14. 18. 21. Quarz. Eisenkiesel. Horustein. Kie- selschiefer. Feuerstein. Krisopras. Plasma. Helio- trop. Kalzedon. Jaspis (exc. Opaljaspis and Por- zellan jaspis). Katzenaui-e. Faserkiesel. Schwimstein. WERN. lloffm. H. 15.1 1. 1. S. CO. 64. 75. 83. 93. 103. 103. 103. 161. 183. 1C9. II. S. 75. Quarz (exc. Quarzsinler). Eiserkiesel. Jaspis. Kieselschiefer. Horn- stein. Feuerstein. Kalzedon. Schwimmkiesel. HAUSM. II. S. 377- 395. 390. 399. 404. 406. 416. Quarz (exc. Kieseltutf'). LEOXH. S. 117. Quarz (exc. Q. hyalin concretionne and Q. resinite). HACY. Traite', T. II. p. 406. Tabl. comp. p. 24. Trait;', 2de Ed. T. II. p. 228. WEISS. Magazin der Gesellschaft naturforschender Freunde zu Berlin. VII. S. 163. KUPFFER. Ann. de Chimie. T. XXV. p. 337. Fundamental form. Rhombohedron. R = 75° 55'* Vol. I. Fig. 7. KUPFFER. a = J 10-894. Simple forms. R (*) ; — R (S) ; 1> (P, z) = 133° 44-', 103° 36', Vorospatak, Transylvania; P + 1 = 124° 33', 137° % ; P + 2 (b) = 121° 14', 157° 44' ; I P (a) = 126° 14', 129° 26' ; | P + 2 (TO) = 122° 10', 150° 36' ; P + x (r) PHYSIOGRAPHY. CLASS it. (P) » (o) = 129° 50'* ; (P)» (*. r . 4 2 Fig. 90. Dauphiny. 2 «/2^' -ffi -jll±? -*<*£>! 4 4 ' 4 4 r(^-fQD)^ Pr+); (P)* ; (P)* («) ; (P + !)• ; (P + GO)' (ft). Char, of Comb. Hemi-rhombohedral, with different faces contiguous to opposite ends of the crystals. Of the prism R + oo, there are generally only the alternating faces, of (P + oo)m the alternating pairs to be met with in the combinations. Combinations. 1. R. [R + °°]. p + pp. R. Sim. Fig. 136. Colour black. Greenland. 2.R. (P)*. [R + °°]t P + OD. Red. Cathe- m rinenburg, Siberia. 3. R. R + l. P + oo. R — oo. Fig. 137. Green. St Gotbard. 4. R — oo. R — 1. R. 5l±^. P + QD. R. (P) ; ^ P — 3 (n) = 1 60° 5', £8° 19' ; P — 1 (o) = 141° V, 56° 8' ; P (c) ; P + 1 = 117° 47', 93° 53'; P + 2 (b) = 107° 41', 113° 6'; -;~ P + 3 = 99° 21', 132° 27'; P + 4 (rj = 95° 39', 143° 2G'; P + OD (J); [P + oo] (Jf); (P — 2)* (a) = 146° 25', 156° 26', 80° 28'; (P — I)3 (z) = 139°54', 151°55'5100°14'; (P)5 (]. Sim. Fig. 101., having the apex replaced. Siberia. £ P — Q&. P. P + 0>. [P + ODj. P + 00. [(P -h oo)3]. Vesuvius. 3. P— QD. P — 1. P. P + 00. [P + OD]. [(P 4- )*]. Orawitza, Bannat. OBDEtt vn. PYfiAMIDAL GARNET. 355 4. P — oo. P — 1. P. (P— 2)3. (P — 1)'. P 4 2. (P)3. (P)4. (P -f- 1)'. P 4- 4. (P4oo)>. [(P4<»)3]. P + oo. [P4o°]. Fig. 96. Vesuvius. Cleavage, P 4 oo and [P -f QD] not very distinct, still less so P — QD. Fracture imperfect con- choidal, uneven. Surface, P — co sometimes uneven and curved ; the prisms striated parallel to their common intersections, the rest of the faces smooth. Lustre vitreous, inclining to resinous, sometimes very distinctly the latter. Colour, various shades of brown, passing into leek-green, pistachio-green, olive-green and oil-green. Streak white. Semi- transparent ... faintly translucent on the edges. If viewed in the direction of the axis, the colours inclined more to yellow, perpendicular to it more to green. Hardness = 6-5. Sp. Gr. = 3*399, a perfectly pure fragment of a crystal of Egerane. Compound Varieties. Massive: composition gra- nular, of various, sometimes considerable sizes of individuals, often strongly connected. There oc- curs also columnar composition, generally of thin individuals, straight and divergent or irregular, faces of composition irregularly streaked. OBSERVATIOKS. 1. The first varieties of pyramidal Garnet, which at- tracted the notice of mineralogists, were those found among the minerals ejected by Mount Vesuvius. With- 356 T PHYSIOGRAPHY. CLASS II. these, the varieties discovered at successive periods, were almost all united. Those found near Egra in Bohe- mia, were, however, considered as a particular species, and from their locality they received the name of Egerane, while that of Vesuvian was retained for the other ; both have been comprised under the name of Idocrase. The only difference that seems to exist between these varieties consists in the relative length of the crystals, which is much greater in Egerane, and the crystals more deeply streaked and altogether less perfectly formed, than those of Vesuvian, which appear in shorter prisms, bounded by a greater number of brilliant planes. The composition of massive varieties is granular in the latter, and columnar in the former. All the colours, however, of Vesuvian and Egerane form a continuous series, in which no constant limits can be fixed. A variety resembling Egerane has been called Lobdile, and Frugardlte ; another from Tellemarken in Norway, of a blue colour, and containing copper, which is supposed to belong to the present species, has been termed Cyprine. 2. Pyramidal Garnet has yielded by analysis the follow- ing results : the two first were obtained by KLAPROTH, the third by Count DUN IN BORKOWSKY. Vesuvian, Vesuvian, Egerane, from Vesuvius. from Siberia. from Bohemia. 41-00. 22-00. 22-00. 3-00. 6-00. 2-00. 1-00. The varieties from Vesuvius and from Fassa in the Tyrol, easily melt into a dark coloured globule, which is pale green in Egerane, and the formation of it accompanied with effervescence. The blueish-grey eight-sided prisms, formed in the iron-slag from Merthyr Tydvil, are consider. Silica 35-50 42-00 Alumina 33-00 1C-25 Lime 22-25 34-00 Magnesia 0-00 Oxide of Iron 7'50 0-00 5-50 Oxide of Manganese 0-25 Potash 0-00 a trace 0-00 ORDER VII. TETRAHEDRAL GARNET. 357 ed by Professor MJTSCHERLICH^OS belonging to the pre- sent species. 3. Some of the varieties of pyramidal Garnet occur in imbedded crystals in a kind of serpentine, containing also decomposed crystals of an unknown mineral in the shape of trigonal dodecahedrons ; others are found massive in rocks and mountain masses, in the cavities of which they appear in a crystallised state. They also occur in veins, but the second kind of their repositories is the most frequent. Py- ramidal Garnet is accompanied by rhombohedral Lime-ha- loide, rhombohedral Talc-mica, various species of the gene- ra Kouphone-spar, Augite-spar and Feld-spar, frequently by dodecahedral Garnet and ihombohedral Quartz, and sometimes by ores of iron and copper, &c. 4. The imbedded crystals, presenting less complicated varieties of crystallisation, have been found on the banks of the Wilui river, and I^ake Baikal in Siberia ; the im- planted complicated crystals occur at Monte Somma, among the fragments ejected by Vesuvius, and have been ori- ginally formed in those cavities of the rock in which they are found. At Haslau near Egra in Bohemia, it occurs in crystals imbedded in rhombohedral Quartz, also in mas- sive varieties of a columnar composition ; in similar cir- cumstances in Finland, where, among others, they are ac- companied by prismatic Titanium-ore. In beds in lime- stone it occurs at Orawitza in the Bannat of Temeswar, and at Mount. Monzoni near Fassa in Tyrol, also near Christiania in Norway, and in magnificent crystals in veins traversing primitive rocks, in the valley of Brozzo and other places in Piedmont. It is found besides in Spain, in Ireland, America, &c. 2. TETRAHEDRAL GARNET. Tetrahedral Garnet or Helvine. JAM. Man. p. 224. Hel- vin. PHILL. p. 244. Kelvin. WERN. Hoffm. H. B. IV. 2. S. 11 2. Helvin. LEONH. S. 430. Helvine. HAUY. Traite', 2de Ed, T, II. p. 333. 358 PHYSIOGRAPHY, CLASS n. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. £ (P) Vol. I. Fig. 13. ; — ~ (*) Vol. I. Fig. 14. Char, of Comb. Semi-tessular with inclined faces. Combination. -. — -. Fig. 158. Cleavage, traces of the octahedron. Fracture un- even. Surface, of one of the tetrahedrons smooth, a little rounded and uneven, sometimes streaked parallel to its edges, of the other rough but even. Lustre vitreous, inclining to resinous. Colour wax-yellow, inclining to honey-yellow and yellow- ish-brown, or also to siskin-green. Streak white. Translucent on the edges. Hardness = 6-0 ... 6-5. Sp. Gr. = 3-100, of a very small quantity. OBSERVATIONS. ,1. According to VOGEL, it consists of Silica 3950. Alumina 15 -65. Oxide of Iron 3775. Oxide of Manganese 3'75. Lime 0-50. Before the blowpipe upon charcoal, it melts in the re- ducing flame with effervescence into a globule of almost the same colour as the mineral. In the oxidating flame the colour becomes dark, and the fusion more difficult. With borax it yields a transparent glass, often coloured by man- ganese. 2. Tetrahedral Garnet has been hitherto found only at S^hwarzenberg in Saxony, in beds in gneiss. It is accom- panied with dodecahedral Garnet-blende, rhombohedraj ORDER Til. DODKCAHEDRAL GARNET. 359 Quartz, octahedral FKior-haloide, and rhouibohedral Urae- iialoide. 3. DODECAHKDUAL GARNET. Dodecahedral Garnet (excepting subsp. 8. and 0.). JAM. Syst. Vol. I. p. 139. Dodecahedral Garnet. Man. p. 224. Garnet. PHII.L. p. 26. Grossular. Melanit. Granat. Allochroit. Pirop, Pireniiit. Kolophonit. WE RX. Hotfin. H. B. I. S. 479. 488. 491. 512. 521. II. 1. S. 371. 373. Ahnandin. Pyrop. Granat. Braunstein- kiesel. Kolophonit. Melanit. HAUSM. II. S. 595.596. 599. 602. 603. 604. Granat. LEONH. S. 426. Grenat. HAUY. Traite', T. II. p. 540. TabL comp. p. 32. Traite', 2de Ed. T. II. p. 313. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H ; Di (P) Vol. I. Fig. 31., Fah- lun, Sweden; A2 (c) Vol. I. Fig. 32; Ci (n) Vol.1. Fig. 34., Botallack, Cornwall; Ti (s) Vol. I. Fig. 35. Combinations. 1. H. D. Fig. 151. the faces of the hexahedron much smaller. Cziklowa, Bannat. 2. D. Ci. Fig. 154. Fracati, near Home. 3. D. Ci. Ti. Arendal, Norway. 4. D. Ci. A2. Ti. Ala, Piedmont. Irregular forms, grains. Cleavage, dodecahedron, indistinct. Fracture con- choidal, more or less perfect, generally uneven. Surface of the hexahedron rough ; the tetragonal icositetrahedron, and the tetraconta-octahedron frequently streaked parallel to the edges of com- bination with the dodecahedron ; the dodecahe- dron itself sometimes streaked parallel to its 360 PHYSIOGRAPHY. CLASS u. edges of combination with the hexahedron. The surface of the grains is uneven, rarely granulated. Lustre vitreous, inclining to resinous in some va- rieties, more nearly the latter. Colour red, brown, yellow, white, green, black ; except some red co- lours, none of them are bright. Streak white. Transparent ... translucent. Hardness = 6-5 ... 7-5. Sp. Gr. rr 3-615, Gros- sular; 3-701, Melanite ; 3-769, brown, common Garnet ; 3-788, Pyrope ; 4 098, crystals of pre- cious Garnet, Tyrol ; 4-125 grains of precious Garnet, Ohlapian ; 4-179, crystals of Almandine ; 4-208, crystals of precious Garnet, Haddam. Compound Varieties. Massive: composition gra- nular, of various sizes of individuals, and often even impalpable, easily separated or strongly coherent ; faces of composition irregularly streaked, uneven or rough. If the composition be impalpable, the fracture becomes uneven and splintery. The com- position is sometimes thick lamellar, and bent, the faces of composition being pretty smooth. OBSERVATIONS. 1. The numerous and manifold varieties of those mine- rals which are at present united within the species of dodecahedral Garnet, present such properties as render it likely, that they will be at some future period distin- guished into several really distinct species. Particularly the limits of hardness and of specific gravity are more distant than we are accustomed to find it in one and the same species. Those inquiries, however, which have been hitherto instituted into their natural-historical properties, are not sufficient to establish clear and constant limits, and in OttDER vii. DODECAHEDBAL GASKET. 361 the present state of Mineralogy we must therefore leave them in that connexion with each other. The distinction introduced among those species which have received parti- cular names and denominations, does not correspond to those properties, for it depends almost entirely upon acci- dental circumstances. Of these species, Grossular occurs only in imbedded crystals of the forms of icositetrahedrons, and combinations of it with the dodecahedron. Its co- lours are confined to asparagus-green and mountain-green. Pyrcnette also occurs only in small imbedded crystals in limestone; these are dodecahedrons, and generally greyish- black, but sometimes so pale as to be greyish-white and semi-transparent. Melanite possesses nearly the same forms as Grossular, generally imbedded, and of a velvet- black colour. Pi/rope occurs only in grains, and is remark- ably distinct by its pure translucency and blood-red colour, which is not found in any other variety, though they ap- proach very near to it. Among the gems commonly con- sidered by jewellers as Spinel, there are some which, in colour, hardness, and specific gravity, agree much more with Pyrope than with dodecahedral Corundum, and therefore very likely belong to the same species. Among the va- rieties called Garnet, we find every simple form and com- bination noticed above among the crystalline varieties, also grains and massive varieties ; it contains likewise every shade of the series of colours, &c., and it is therefore only in the particular union of several of these properties, that we must look for the distinction of the above-mentioned species. The colour of precious Garnet is always red, its crystals are formed imbedded, it is the only variety that occurs in grains, and if compound, it presents lamellar composition. Common Garnet seldom occurs in red colours, and these are of dirty tinges ; its crystals are generally im- planted, and the composition granular, but not impalp- able. Colophonite is a compound variety of yellowish- brown and reddish-brown, or oil-green and honey-yellow colours, consisting of roundish particles of composition, 362 PHYSIOGRAPHY. CLASS II. which may be separated with great facility. It should be observed, however, that frequently varieties of paratomous Augite-spar are called Colophohite in collections. If the composition be impalpable, or the particles of a granular composition so intimately connected that they cannot be distinguished from each other, Allochroite is formed, a va- riety which is often mechanically mixed with minerals fo- reign to the species. 2. The ingredients of dodecahedral Garnet have been found as follows : Grossular. Mt.-Iar.Ue. Precious Garnet. Colombo- Allo. chroite. I'yreneite. P>roi>e. Silica 44-00 35-50 35-75 37-00 35-00 43-00 40-00 Alumina 8-50 6-00 27-25 13-50 8-00 16-00 28-50 Lime 33-50 32-50 o-oo 29-00 30-00 20-00 3-50 Ox. of Iron 12-00 24-25 36-00 7'50 17-00 16-00 16-50 Ox. of Man. a trace. 0-40 0-25 4-75 3-50 o-oo 0-25 KLAP. KLAF. KLAP. SIMON. VAUQ. VAUQ. KLAP. Besides these, Colophonite contains 6-5 per cent, of mag. nesia, 0-5 oxide of titanium, and 1-0 water, Allochroite 6-0 of carbonate of lime, Pyreneite 4-0 of water, and Pyrope 10*0 of magnesia and 2-0 chromic acid. In general the varieties of the present species present great differences in regard to their mixture, only a few of which have been in- dicated above. Before the blowpipe they melt pretty uni- formly without effervescence into a black globule present- ing a vitreous fracture. Some varieties present a slight effervescence, but finally yield the same result. The bead obtained by melting is frequently attracted by the magnet. 3. Though dodecahedral Garnet cannot be said with pro- priety to enter into the composition of rocks, it occurs in many of them in grains and imbedded crystals, as in gra- nite, gneiss, but particularly in mica-slate, ehlorjte-slate, •white-stone, serpentine, in various kinds of rocks consider- ed as lava, more sparingly in limestone. Precious Gar- net occurs in slaty primitive rocks ; Grossular and Py- rope are found in serpentine, the latter also in other rocks, through the decomposition of which it is brought inte the ORDER Vii. DODECAHEBRAL GARNET. 365 soiL Melanite is imbedded in a kind of lava, but occurs also implanted in the geodes ejected by Vesuvius, and Pyreneite in limestone. Common Garnet is likewise one of those species occurring at Mount Vesuvius, along with pyramidal Garnet, several species of the genus Feld- spar, &c. : much more frequently, however, it is found in beds, consisting either wholly or for the greater part of its varieties, accompanied by octahedral Iron-ore, several spe- cies of Augite-spar, &c. Thus also are found Allochroite and Colophonite. Some varieties occur in veins traversing serpentine and other rocks. 4. Several of the varieties mentioned above have been found only in a few localities. Grossular occurs along with pyramidal Garnet in Kamtschatka, in a kind of serpentine ; Melanite at Frascati and Albano near Rome ; Pyrope near Bilin in Bohemia, and in the serpentine of Zoblitz and the forest of Zell in Saxony ; Pyreneite near Bareges in the Pyrenees. Precious Garnet, sometimes in large but not very transparent crystals, and often covered with a coat of chlorite, occurs at Fahlun in Sweden, and in many localities of the Tyrol, Carinthia, Stiria, Switzerland, Hungary, &c. The varieties presenting lamellar compositions are found in Greenland, common Garnet in large quantities at Brei- tenbrunn, Berggiesshubel, Geyer, and other places in Saxony, at Drammen and Arendal in Norway, Fahlun, Longbanshyttan, &c. in Sweden, at Orawitza in the Ban- nat, at Dobschau and Rezbanya in Hungary, at Saldenho- fen in Stiria, in Siberia, and many other places. Colopho- nite is known from Arendal, Ailochroite from Drammen, and curious varieties of the latter of yellowish-white and grass-green colours also from the valley of Zem in Salz- burg. The transparent crystals of precious garnet, called Ahnandinc, are chiefly brought from Ceylon and Pegu, where they occur in the sand of rivers. A fine variety ap- proaching in colour to Pyrope, is found at Elie in Fife- shire. 5. Transparent varieties of dodecahedral Garnet are used as gems, but are not highly prized. Among these, how. 364 PHYSIOGRAPHY. CLASS n. ever, Pyrope is preferred to the rest, if pure and of consi- derable magnitude. Common Garnet is useful as a flux of iron-ores, and is in some countries called Green Iron-stone. 6. From the species of dodecahedral Garnet two sub- stances are distinguished by HAUY, which may be here shortly noticed. i. Aplome. HAUY. Trait^, 2de Ed. T. II. p. 538. Form tessular. Combinations observed, 1. H. D. Fig. 151, the faces of the hexahedron small; 2. D. Ci.Fig. 154. Cleavage, traces of the hexahedron. Fracture uneven. Surface of the dodecahedrons streaked parallel to the edges of combination with the hexahedron, which, however, is not the case in the cleavable varieties. Lustre vitreous, inclining to resinous ; high degrees upon faces of crystal- lisation, low degrees in the fracture. Colour brown, some- times yellowish. Streak white. Translucent on the edges ... opake. Brittle. Hardness = 7-0 ... 7-5 (it scratches rhombohedral Quartz). Sp. Gr. = 3-444, HAUY. It has also been found massive. According to LAUGIER, Aplome consists of Silica 40-0. Alumina 20'0. Lime 15-5. Oxide of Manganese 2-0. Ferriferous Silica 2'0. There was a loss of 7-0. Before the blowpipe it melts into a black globule. The localities are, the banks of the river Lena in Siberia, Schwarzenberg in Saxony and Bohemia. Small brilliant, cleavable crystals are found in England. ii. Essonite. Dodecahedral Garnet, subsp. 8th. JAM. Syst. Vol. I. p. 162. Prismatic Garnet or Cinnamon-Stone. Man. p. 228. Cinnamon-Stone. PHILL. p. 32. Kaneelstein. WEHN. Hoffm. H. B. I. S. 417- Idokras. HAUSM. OHDEBVU. DODECAHEDRAL GARNET. S65 II. S. 622. Hessonit. LEONH. S. 433. Kaneelstein. HAUY. TabL comp. p. 62. Essonite. Traite, 2de Ed. T. II. p. 541. The forms are said by HAUY to be prismatic, and traces of cleavage parallel to a prism of 102° 40'. It is generally found in grains. Fracture imperfect and small conchoidal, uneven. Surface uneven and gibbous. Lustre vitreous, inclining to resinous. Colour intermediate be- tween hyacinth-red and orange-yellow. Streak white. Transparent ... translucent. Hardness = 7*0 ... 7'5. Sp. Gr. = 3-636. It also occurs massive, presenting granular composition. It will depend upon the investigations of the regular forms of cinnamon-stone, whether or not it is to be consi- dered as a species of its own. If these belong to the pris- matic system, as is indicated by HAUY, no doubt can exist in regard to the propriety of his erecting it into a particu- lar species. But the close agreement of all its properties with those of dodecahedral Garnet, and the tessular forms inferred from the optical observations of M. BIOT and Dr BREWSTER, which are not contradicted by HAUY, who quotes simple refraction among the characters, render it ex- tremely probable, that it is a variety of dodecahedral Garnet. Cinnamon-stone consists, according to KLAPHOTH, of Silica 38-30. Alumina 21-20. Lime 31-25. Oxide of Iron 6-50. Itdoes not at first assume a darker colour before the blowpipe but melts easily into a brownish-black globule. It occurs in the sand of rivers and in primitive rocks with prismatic Augite-spar in Ceylon. It is found massive at Kincardine in Ross-shire. But it is difficult to quote localities, as the varieties can be hardly distinguished from others of dode- cahedral Garnet. It is used as a gem, which fetches a good price, if large, well coloured and transparent, and goes ge- nerally by the name of Hyacinth. 38G PHYSIOGRAPHY". CLASS n. 5. PRISMATOIDAL GARNET. Prismatic Garnet or Grenatite. JAM. Syst. Vol. I. p. 166. Prismatoidal Garnet or Grenatite. Man. p. 229. Stau- rolite. Grenatite. PHILL. p. 82. Staurolith. WERN. Hoffin. H. B. I. S. 515. Staurolith. HAUSM. II. S. 629. Staurolith. LEONH. S. 424. Staurotide. HAUY. Traite', T. III. p. 93. Tabl. comp. p. 43. Traite', 2de Ed. T. II. p. 338. Fundamental form. Scalene four-sided pyramid. P = 104° 49', 99° 22', 125° 33'. Vol. I. Fig. 9. HAUY. a : b : c = 1 : *J 0-5625 : J 0-5. Simple forms. P — oo (P) ; Pr (r) = 70° 32' ; (Pr + QD)5 (M) = 129° 31' ; £ r + oo (o). Char, of Comb. Prismatic. Combinations. 1. P — oo. (Pr-{- oo)5. Sebes, Tran- sylvania. 2. P — oo. (Pr -f- oo)5. £ r + oo. Spain. 3. P— -oo. Pr. (Pr+)3. f r + oo. Fig. 12. St Gothard. Cleavage, Pr + oo perfect, but interrupted, traces of (Pr + oo) 3 . Fracture conchoidal, uneven. Surface, P — GO sometimes very rough and cor- roded, hollowed out in the centre. The rest of the faces generally of the same quality, either rough or smooth. Lustre vitreous, inclining to resinous. Colour red- dish-brown, or brownish-red, very dark. Streak white. Translucent, frequently only on the edges. Hardness = 7-0 ... 7-5. Sp. Gr. = 3-724, crystals from St Gothard ; that of the common twin- o»DEU Til. PKISMATOIUAL GARNET. crystals from Spain, the substance of which is less homogeneous, is between 3-3 and 3-4. Compound Varieties. Twin-crystals. 1. Face of composition parallel, axis of revojution perpen- dicular to a face of f Pr = 90°; 2. Face of com- position parallel, axis of revolution perpendicular to a face of P. .The individuals in both cases are continued beyond the face of composition, and pro- duce cruciform groupes, the crystals crossing each other in the first case at right angle?, in the second at angles of 60° and 120°. By the addition of a third individual to the latter, groupes resembling stars, with six radii are forms. There are examples of composition, parallel to both kinds of faces at once. OBSERVATIONS. 1. According to an analysis by VAUQCELIK, of the va- riety from Brittany, and another by KLAPROTH, of the variety from St Gothard, prismatoidal Garnet consists of Silica 33-00 37*50. Alumina 44-00 41-00. Lime 3-84 0-00. Magnesia 0-00 0-50. Oxide of Iron 13-00 18-25. Oxide of Manganese 1-Ofr 0-50. It assumes a dark colour before the blowpipe, but does not melt. 2. This species occurs in imbedded crystals in primitive rocks, particularly in mica-slate, in simple and compound crystals, accompanied by prismatic Disthene-spar, dodeca- hedral Garnet, &c. 3. Simple crystals occur in St Gothard in Switzerland, and the Greiner Mountain in Zillerthal in the Tyrol, some- times curiously aggregated with crystals of prismatic S68 PHYSIOGRAPHY. CLASS ir. Disthene-spar, into a continuous mass with parallel axes. Mr ROSE first observed that the perfect planes of cleav- age of the two crystals always coincide. Less perfect are the varieties from Sebes in Transylvania. Twin-crys- tals occur at St Jago de Compostella in Spain, and Oporto in Portugal. There occur likewise several varieties in France, in Aberdeenshire, and several of the isles in Scot- land ; in Brazil; and near Philadelphia hi North America. GENUS XII. ZIRCON. 1. PYBAMIDAL ZIRCON. Pyramidal Zircon. JAM. Syst. Vol. I. p. 29. Man. p. 230. Zircon. PHJLL. p. 90. Zirkon. Hiazinth. WERX. Hoffm. H. B. I. S. 396, 40?. Zirkon. HAUSM. II. S. 618. Zirkon. LEONH. S. 391. Zircon. HAUV. Traite, T. II. p. 465. Tabl. comp. p. 28. Traite,, 2de Ed. T. II. p. 291. Fundamental form. Isosceles four-sided pyramid. P = 123° \W, 84° 2(X. Vol. I. Fig. a R. G. a = V 0-8204. Simple forms. P — oo ; P — 1 (t) = 135° 10', 65° 17' ; P (P), Expailiy, France ; P + 2 = 103° 31', 122° 12' ; -;- P + 3 (u) = 96*51', 139° 35' ; P + oo (/) ; [P + oo] (*) ; (P)3 (a) = 132° 43', 147° 3', 127° 27'; (P)4 (y) ; (P)5 (z). Char, of Comb. Pyramidal. Combinations. 1. P. P + oo. St Gothard, Swit- zerland. 2. P. [P + OB]. Sim. Fig. 97. Ceylon. 3. P. (P)5. P + oo. [P -f- »]• Ohlapian. 4. P. (P)'. ^-j P + 3. P + a. [P + oc]. Vol. I. Fig. 68. Frederiksvarn, Norway. ORDER VII. PYRAMIDAL ZIRCON. 369 5. P — - 1. P. (P)3. (P)4. P + oo. [P -f QD]. Saualpe, Carinthia. 6. P— 1. P. (P)3. (P)4. (P)5. P+oo. [P + oo]. Fig. 99. Saualpe. Irregular forms, grains. Cleavage, P and P -f- GO ; the latter more distinct, but none of them of high degrees of perfection. Fracture conchoidal, uneven. Surface ; P — GO very rough ; P — 1 also rough, though less so than P — - oo ; [P + oo] often both rough and uneven. The other faces are nearly all alike in respect to their physical qualities, often particu- larly smooth and shining ; the grains and pebbles are uneven and often rough, but some- times also very smooth. Lustre, more or less perfectly adamantine. Colour red, brown, yellow, grey, green, white ; with the exception of some red tints, none of them are bright. Streak white. Transparent .., trans- lucent, sometimes but faintly. Hardness = T5. Sp. Gr. = 4-505, of a crystal- lised variety from the Saualpe, Carinthia. OBSERVATIONS. 1. The reason why Hyacinth and Zircon have so long been separated from each other as distinct species, we find in the circumstance, that the specific gravity of Essonite (p. 364.), to which the name of Hyacinth likewise had been applied, was supposed to refer to those varieties of pyra- midal Zircon, which possess the same colour, while the specific gravity of the rest was known, and constituted one of the characters of the species Zircon. But even after VOL. II. 2 A 870 PHYSIOGRAPHY. CLASS n. this error had been discovered, several mineralogists yet continued to divide those varieties, and grounded the dif- ferences upon forms of crystallisation, colour, &c. all of which can be of no avail, if we rightly consider the species in Mineralogy. Hyacinth possesses the brightest colours, least inclining to grey, and such combinations, in which the regular four-sided prism, in combination with the fundamental pyramid, is in a diagonal position, as in Fig. 97-> either alone, or at least presents broader faces than the other prism, in parallel position with P, and which replaces the lateral edges of the pyramid, and of the other prism. Both, crystals and grains of Hyacinth are smooth and shining, those of Zircon are frequently rough. Zircon besides possesses tints of colour, that in- cline much more to grey. The differences in cleavage, supposed to take place between the two varieties, do not exist, at least they are not greater than we are ac- customed to find them in other species. Hence it is evi- dent that all the varieties must be necessarily included within one and the same species, which then appears as one of the most remarkable in the whole mineral kingdom. 2. Zircon and Hyacinth consist, according to KLAP- ROTH, Of Zirconia 69-00 70-00. Silica 26-50 25-00. Oxide of Iron 0-50 5-00. Before the blowpipe it loses its colour, but does not melt. 3. The varieties of this species have always been found in imbedded crystals in mountain masses, or in beds includ- ed in them. They seldom form small masses, consisting of several crystals. From these repositories it is washed into the sand of rivers, where it is notunfrequently met with. 4. In the Saualpe in Carinthia, pyramidal Zircon occurs in a bed of Albite and of prismatoidal Augite-spar, called Zoisite, in gneiss ; the varieties from New Jersey and other localities in North America, from Greenland, from Ceylon, &c. occur likewise in gneiss or in talcose rocks ; those from Frederiksvarn in Norway, in zircon-syenite. Near Puy onDER vii. PRISMATIC GADOLIXITE. 371 iii France it occurs in amygdaloid. In Ceylon, in France, at Ellin in Bohemia, at Ohlapian in Transylvania, &c. pyramidal Zircon occurs in the sand of rivers ; it is com- monly found with the native Platina. Among the residue from the gold stream works in Transylvania, they are fre- quently of a white colour ; but there are likewise bright hyacinth-red ones of the elegant form (P)3. [P -f co], the eight-sided pyramid not being modified by any faces conti- guous to its apices. Similar varieties are found among the Scorza, or arenaceous Epidote (prismatoidal Augite-spar) from M uska on the Aranyos in the same country. They are very small. 5. Pyramidal Zircon is used as a gem, but of no high value. Several varieties from Ceylon used formerly to be called Jargon de Ceylon, and sold as an inferior kind of diamonds, on which account they were denominated Jar- goon of diamond. GENUS XIII. GADOLINITE. 1. PRISMATIC GADOLINITE. Prismatic Gadolinite. JAM. Syst. Vol. I. p. 170. Man. p. 231. Gadolinite. PHI LI., p. 105. Gadolinit. WERN. Hoffm. H. B. III. 2. S. 303. Gadolinit. HAUSM. II. S. 608. Gadolinit. LEONH. S. 500. Gadolinite. HAUY. Traite', T. III. p. 141. Tabl. comp. p. 47. Traite', 2de Ed. T. II. p. 440. Fundamental form. Scalene four-sided pyramid. P = 156° 55', 111° 6', 73° 44'. Inclination of the axis = 0. Vol. I. Fig. 41. HAUY. a:b:c:d=l:4:V2:0. Simple forms. r (0 = 156° 55'; (Pr -f oo)5 (M) = 109° 28'; (? + oo)4 (u) = 70° 372 PHYSIOGRAPHY. CLASS II. Char, of Comb. Henri-prismatic. Combination. iJj. -|. (Pr + oo)5. (?+ oo)4. Pr+ «. Cleavage, so imperfect, that its direction has not been ascertained. Fracture conchoidal. Lustre vitreous, inclining to resinous. Colour greenish-black, very dark. Streak greenish-grey. Translucent on the edges, almost opake. Hardness = 6-5 ... 7-0. Sp. Gr. = 4-238. Compound Varieties. Massive : composition impalpable, fracture conchoidal. OBSERVATIONS. 1. The above mentioned forms are given on the autho- rity of HAUY, but, according to his own statement, they are only approximations.* 2. According to BERZELIUS, prismatic Gadolinite con- sists of Yttria 45-00. Protoxide of Iron 1 1 -43. Protoxide of Cerium 17-92. Silica 25-80. Before the blowpipe it decrepitates, if it has not been heated with the necessary precaution ; and does not melt, except in very small splinters. If heated with precaution upon charcoal, it incandesces at once, and its colour be- comes paler. In nitric acid it loses its colour, and is con- verted into a jelly* * Mr PHILLIPS describes an oblique rhombic prism of 115°, the terminal plane of which is inclined to the obtuse edge at an angle of 98°. It is combined with a horizontal prism of 120° in the direction of the short diagonal of the oblique prism, and two faces of a pyramid to which the horizontal prism be- longs, meeting at an angle of 120° ; they replace the obtuse edges of combination in the oblique prism. H> ORDER VIII. PRISMATIC TITAXIUM-ORE. 373 3. Prismatic Gadolinite occurs in gneiss and granite, in repositories that have been considered as beds and as veins. It is chiefly accompanied by prismatic Feld-spar and Al- bite, rhombohedral Quartz, &c. Its localities are Ytterby near Stockholm, and Finbo and Broddbo near Fahlun in Sweden. It is likewise found in Greenland. ORDER VIII. ORE. GENUS I. TITANIUM-ORE. 1. PRISMATIC TITANIUM-ORE. Prismatic Titanium.Ore or Sphene. JAM. Syst. VoL III. p. 121. Man. p. 232. Sphene. PHILL. p. 262. Braun- Menakerz. Gelb-Menakerz. WERN. Hoffm. H. B. IV. 1. S. 260. 263. Spheu. HAUSM. II. S. 613. Ti- tanit. LEONH. S. 596. Sphene. Titane silice'o-cal- caire. HAUY. Traite', T. III. p. 114. T. IV. p. 307. Titane siliceo-calcaire. Tabl. comp. p. 116. Titane cal- care'o-siliceux. Traite', 2de Ed. T. IV. p. 353. G. ROSE. De Sphenis atque Titanitae systemate crys- tallino. BeroL 1820. Fundamental form. Scalene four-sided pyramid. P = , 89° 46', 131° 8'. Inclination of the axis = 8° 18' in the plane of the short dia- •gonal. Vol. I. Fig. 41. ROSE. a : b : c : d = 6-35 : 4-05 : 4-97 : I. Simple forms. P — QD (v); — (r) == 113° 37'; — * p — a m - 133° 4,8' ; — C«0£ ss\ _ 67o 2 2 46'; (Pr + OD)* (n) = 136° 8'; ^rp^.! (O) = 155° 35'; — )». Fig. 47. Arendal. rr. £r+ oo. StGothard, Switzerland. Cleavage; sometimes distinct in the direction of "P "PT ^ T^ ^ — ; less distinct in that of — and — - — ^~- — Fracture imperfect conchoidal, uneven. Surface, — and — - — ^"— almost always faintly streak- ed parallel to the edges of combination with T> ^Pr^3 — ; — 2 at t^le same time parallel to those with f r — 1, with (Pr + oo)5, and with its own edges; — — — — is often rounded, sometimes also — — . The remaining faces are smooth, and often possess high degrees of lustre. Lustre adamantine, sometimes inclining to resinous. ORDER Viii. PRISMATIC TITANIUM-ORE. 375 Colour brown, yellow, grey, green ; they are not lively, some pistachio-green ones excepted. Streak white. Transparent ... translucent on the edges. Hardness = 5-0 ... 5-5. Sp. Gr. = 3468, of a massive yellowish-grey variety from Norway. Compound Varieties. Twin-crystals : faces of composition parallel, axis of revolution perpendicu- "pj» Jar to — — ; sometimes the individuals are conti- nued beyond the face of composition. Massive : composition granular or lamellar ; the first are very strongly connected. OBSERVATIONS. 1. The preceding regular forms are given entirely on the authority of Mr G. ROSE. Most of the forms depend upon the parallelism and situation of some of their edges of com- bination, yet some doubt still remains in regard to the best position to be chosen for the crystals of the species, which may be probably brought to a still higher degree of simplicity. The two species of the Wernerian system, the Brown and the Yellow Menachlne-ore^ or Titanite and Sphene^ differ chiefly in their colours, and the degrees of transparency connected with them. The first is brown, and almost entirely opake, while the last is of various pale brown, yellow, green, and grey colours, and at least translucent. These two species, like Hyacinth and Zircon, or Beryl and Emerald, are frag- ments of the intimately connected series of varieties which together form the natural-historical species of prismatic Titanium-ore. 2. The varieties of the present species consist of Lime 33-00 32-20. Oxide of Titanium 33-00 33-30. Silica 35-00 28-00. Oxide of Manganese a trace. KLAPROTH. 0-00. CORDIER. 376 PHYSIOGRAPHY. CLASS II. Before the blowpipe the yellow varieties do not change their colour ; all the rest become yellow. They intumesce a little, and melt on the edges into a dark-coloured enamel. They are soluble in heated nitric acid, and leave a siliceous residue. 3. Prismatic Titanium-ore occurs in small nodules or crystals imbedded in gneiss, and beds of syenite and other trap-rocks, belonging to them, or also to more recent classes of mountains. It is met with in metalliferous beds with ores of iron, several species of Augite-spar and Feld-spar, &c., and likewise in those veins which traverse primitive rocks, and which are considered as the most ancient produc- tions of that kind, as they consist of the same species as these rocks themselves. 4. Prismatic Titanium-ore occurs in several districts of the Saualpe in Carinthia, imbedded in coarse-grain- ed gneiss. At Hafnerzell in the district of Passau it occurs in a bed in gneiss, consisting almost entirely of Augite-spars and Feld-spars, at Windisch-Kappel in Ca- rinthia, and near Dresden in Saxony, in similarly com- pound rocks of a newer date. In beds of iron-ore it occurs particularly at Arendal in Norway ; in veins at St Gothard in Switzerland, in the Felberthal in Salzburg, and in many other places in the Alps. It is found, besides, in many countries, as almost every syenite contains small crystals of it ; for instance, the variety from Strontian and other places in Scotland. . PERITOMOUS TITANIUM-ORE. Prismato-Pyramidal Titanium-Ore. JAM. Syst. Vol. III. p. 128. Man. p. 234. Titanite. Nigrine. PHILL. p. 258. 259. Rutil. Nigrin. WERN. Hoffm. H. B. IV. 1. S. 252. Syst. p. 26. Eisentitan ? Rutil. HAUSM. I. S. 318. 319. Rutil. LEONH. S. 147. Titane oxyde'. HAUY. Traite', T. IV. p. 296. Tabl. conip. p. 115. Trait^, 2de Ed. T. IV. p. 333. ORDER vui. PERITOMOUS TITANIUM-ORE. 377 Fundamental form. Isosceles four-sided pyramid. P = 117° 2', 95° 13'. Vol. I. Fig. 8. HAUY. a = Vl-2- Simple forms. P — 1 = 128° 41', 67° 58' ; P (c) ; P + QD (/); [P + oo] (J/); (P + oc)3 (h) = 126° 5% 12", 143° 7 48". Char, of Comb. Pyramidal. Combinations. 1. P. (P -f x)3. Orisons. 2. P. P + oo. [P + ooj. Sim. Fig. 101. Teinach, Stiria. 3. P — 1. P. P + QD. [P -F oo]. Sim. Fig. 101. Saualpe, Carinthia. Cleavage, P + oo and [P -f oc], perfect, but very much interrupted. Fracture conchoidal, uneven. Surface, P and P — 1, either smooth or rough, but both of the same physical quality : the prisms vertically streaked. Lustre metallic adamantine. Colour reddish-brown, passing into red, sometimes yellowish. Streak very pale brown. Translucent ... opake, some- times in a strong light transparent. Hardness = 6-0 ... 6-5. Sp. Gr. = 4 249, the dark coloured variety from Ohlapian. Compound Varieties. Twin crystals very fre- quent, axis of revolution perpendicular, face of composition parallel to a face of P — 1. The composition produces geniculated groupes, and is often repeated in several geniculations. Thin and long individuals produce after this law a reticu- lated composition. Massive : composition granular, 373 PHYSIOGRAPHY. CLASS n. the individuals being of various sizes and strongly connected. OBSERVATIONS. 1. If pure, it is entirely composed of oxide of titanium, T, containing, according to Mr H. ROSE, 66-05 of metal, and 33-95 of oxygen. By itself it is infusible before the blowpipe, but gives with borax in the reducing flame a yel- low glass, which assumes an amethyst colour when farther reduced. 2. It occurs generally in imbedded crystals, either in the masses of rhombohedral Quartz engaged in gneiss, mica-slate, and other rocks, or in beds, consisting of rhom- bohedral Quartz, dodecahedral Garnet, several species of Augite-spar, &c. It is sometimes found massive in metal- liferous beds. It is likewise a production of ancient veins, and often inclosed in transparent crystals of rhombohedral Quartz. It occurs in the shape of pebbles in some gold stream works. 3. Imbedded crystals in Quartz have been found at Ro- senau in Hungary, Teinach on the Bacher in Stiria, and various localities along the chain of the Alps, also at Cri- anlarich in Perthshire, and other places in Scotland, &c. Very perfect crystals occur in the Saualpe, and in the neighbourhood of Windisch-Kappel in Carinthia ; massive varieties in the metalliferous beds of Arendal in Norway. Switzerland and Savoy include many localities where it occurs in veins, sometimes in reticulated shapes. Peb- bles have been found at Ohlapian in Transylvania, and called Nigrine on account of their dark colour. At St Yrieix in France and in the province of Guadalaxara in Spain, the well known twin-crystals occur, often of very considerable dimensions. St Gothard is the locality of some finely crystallized varieties, associated with rhombo- hedral Iron-ore. The present species occurs in greater or smaller quantities in many countries, as in Germany, Bo- hemia, Salzburg, Piedmont, Siberia, America, &c. Beau- ORDEtt Vin. PYRAMIDAL TITAXIL'M-OIIE. 379 tiful varieties of it, engaged in transparent Quartz, have been brought from Brazil. 4. The oxide of Titanium has been used in painting upon porcelain. 3. PYRAMIDAL TITANIUM-ORE. Pyramidal Titanium-Ore or Octahedrite. JAM. Svst. Vol. III. p. 137- Man. p. 235. Anatase- Octahedrite. PHILL. p. 25J. Oktaedrit. WERX. Hoifra. H. B. IV. S. 249. Anatas. HAUSM. I. S. 322. Anatas. L.EONH. S. 145. Anatase. HAUY. Traite', T. III. p. 129. Titane anatase. Tabl. comp. p. 116. Traite', 2de Ed. T. IV. p. 344. Fundamental form. Isosceles four-sided pyramid. P = 97° 56', 126° 22'. Vol. I. Fig. 8. R. G. a = V 6-240. Simple forms. P — x (o) ; J P — 4 (r) = 148° 5(X, 53° & ; P — 1 = 104° 3', 120° 58' ; P (P) Dauphiny; P + 1 (q) = 94° 15', 148° 23'; P+oo/dP — 7)*? (*). Char, of Comb. Pyramidal. Combinations. 1. P — oo. P. Sim. Fig. 92. 2. | P — 4. P. Sim. Fig. 105. 3. P — x. P — 1. P. P + 1. 4. p— oo. I P— 4. (|P — 7)4. P. P-f-1. Fig. 100. All of them from Dauphiny. Cleavage, P — oo and P, both perfect. Fracture conchoidal, scarcely observable. Surface smooth and shining, P + co and sometimes also P, ho- rizontally streaked. Lustre metallic adamantine. Colour, various shades of brown, more or less dark, also indigo-blue. Streak white. Semi-transparent . . . translucent. 380 PHYSIOGRAPHY. CLASS II. Hardness = 55... 6-0. Sp. Gr. = 3-826. OBSERVATIONS. 1. The present species consists of oxide of titanium, like the preceding one, but it is purer itself, and also the colours of the fluxes, as obtained by the action of the blowpipe, are purer. 2. The only mode of occurrence of pyramidal Titanium, ore in nature is in narrow irregular veins, consisting of those species which constitute the rocks themselves, and it is ac- companied by Albite, rhombohedral Quartz, several species of Talc-mica and Augite-spar, prismatic Axinite, arid Crich- tonite. Its chief localities are Bourg d'Oisans in Dauphiny and Switzerland ; but it has been found also in Cornwall, in Norway, in Spain, and Brazil. GENUS II. ZINC-ORE. Red Zinc or Red Oxide of Zinc. JAM. Syst. Vol. III. p. 447. Prismatic Zinc-Ore. Man. p. 235. Red Oxide of Zinc. PHILL. p. 353. Zinkoxyd. LEONH. S. 312. Zinc oxide' ferrifere lamellaire brun rougeatre. HAUY. Traite', 2de Ed. T. IV. p. 179. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Cleavage, P -f- oo — 125°* (about), distinct ; less distinct, Pr-f ooandPr-|- oo, traces of (Pr-f oo)5. Fracture conchoidal. Lustre adamantine. Colour red, inclining to yel- low. Streak orange-yellow. Translucent on the edges. * According to Messrs BREITHAUPT and PHILLIPS, this angle is = 120°, and the prism in combination with Pr + w a regular one. H. ORDER Vlll. OCTAHEDRAL COPPER-ORE. 381 Brittle. Hardness = 40 . . . 4-5. Sp. Gr. = 5-432. Compound Varieties. Massive: composition gra- nular, individuals strongly connected. OBSERVATIONS. 1. According to an analysis by BRUCE, and another by BERTHIER, the prismatic Zinc-ore consists of Oxide of Zinc 92-00 88-00. Oxide of Iron and Manganese 8-00 12-00. It becomes dull on being exposed to the air, and is covered with a white coating. Alone it is infusible before the blowpipe, but yields a yellow transparent glass with borax. It is soluble without effervescence in nitric acid. 2. It occurs massive, mixed with rbombohedral Lime- haloide and dodecahedral Iron -ore, probably in beds, and is found in large quantities in several localities in Sussex county, New Jersey. It bids fair to become very useful in extracting zinc. It is set free in several metallurgical pro- cesses, and occurs crystallised in six-sided prisms of a yel- low colour in the founderies of Kb'nigshutte in Silesia, ac- cording to MlTSCHERLICH. GENUS III. COPPER-ORE. 1. OCTAHEDRAL COPPER-ORE. Octahedral Copper-Ore. JAM. Syst, Vol. III. p. 1 40. Oc- tahedral Red Copper-Ore. Man. p. 236. lied Oxide of Copper. Oxydulated Copper. PHILL. p. 306. Roth- Kupfererz. Ziegelerz. WERN. Hoffm. H. B. III. 2. S. 89. 98. Kupferroth. Kupferbraun. HAUSM. I. S. 237- 240. Roth-Kupfererz. LEONH. S. 267- Cuivre oxide rouge. HAUY. Traite, T. III. p. 555. Cuivre oxidule'. Tabl. comp. p. 88. Traite', 2de Ed. T. III. p. 462. PHILLIPS. Trans. Geol. Soc. Vol. I. p. 23. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (/) ; 6 (P), Vol. I. Fig. 2. ; fo 382 PHYSIOGRAPHY. ctASS ir. (r) Vol. I. Fig. 31. ; A*, Vol. 1. Fig. 32. ; B, Vol. I. Fig. 33.; Ci, Vol. I. Fig. 34. ; Ti, Vol. I. Fig. 35. Char, of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3 and 4. 2. H. D. Fig. 151. 3. H. O. D. 4. H. O. D. B. Fig. 155. 5.HO.D.C*. 6.H.O.D.A«.B.Ci.Ti. Cleavage, octahedron, with smooth faces, but very much interrupted. Fracture conchoidal, uneven. Surface generally very smooth and shining, and everywhere the same. Lustre adamantine, sometimes metallic adamantine or imperfect metallic. Colour between cochineal- red and lead-grey ; also pure cochineal-red, and in capillary crystals almost carmine-red. Streak several shades of brownish-red, shining. Semi- transparent ... translucent on the edges. Brittle. Hardness = 3-5 ... 4-0. Sp. Gr. — 5 992, crystals from Chessy. Compound Varieties. Massive : composition gra- nular, individuals of various sizes, or even impal- pable. In the latter case, fracture becomes flat conchoidal or even, the surface of the fracture glim- mering. Sometimes earthy. OBSERVATIONS. 1. Those varieties which consist of friable particles, and present an earthy fracture, and which are besides often mixed with oxide of iron, or several Malachites, &c., con- stitute the Tilc-orc, which was formerly considered as a par- ticular species, and divided into earthy and indurated Tile- ORDER viii. OCTAHEDRAL COPPER* ORE. 283 ore. Red Copper-Ore itself, the remaining varieties of the present species, was divided into three subspecies, the fo- liated, which contains those crystallised varieties which are not capillary, and compound cleavable ones ; the capillary, which comprehends very thin filiform crystals, reticulated or in velvety groupes ; and the compact, which refers to im- palpable compositions, and is to the foliated varieties in the same relation as compact limestone is to calcareous spar, or compact Lead-glance to common Lead-glance. 2. Octahedral Copper-ore consists of Copper 91-00 80-50. Oxigen 9-00 KLAPROTH. 11-50. CHENXEVIX. It is the protoxide of copper, Cu, which contains 88-78 cop- per and 11-22 oxygen. In the reducing flame of the blow- pipe, it is reduced upon charcoal into a globule of copper. It is soluble with effervescence in nitric acid, but without effervescence in muriatic acid. 3. Octahedral Copper-ore is found in beds and veins in several rocks. It is accompanied by various other ores of copper and iron, and rhombohedral Quartz. 4. Very fine varieties of this species have been found in the Bannat of Temeswar, particularly the vicinity of Mol- dawa ; near Catharineburgh in Siberia, at Chessy near Lyons in France ; and these occur in beds, at least those of France, in sandstone, and those of Hungary in gneiss. Not inferior to any of the preceding ones, and in consider- able quantity, the present species is met with in the well known tin and copper veins of Cornwall. The chief locali- ties of capillary groupes are Cornwall and Rheinbreitbach on the Rhine. Octahedral Copper-ore also occurs in Saxony, in the district of Siegen in Prussia, in Norway, in Peru and Chili. Tile-ore is found among others in the Bannat, and at Camsdorf and Saalfeld in Thuringia. It is frequent- ly produced in the slags formed in the last process of melting copper, as has been observed by Professor MITSCHERLICH. Copper vessels and other objects made of that metal, and long exposed to the action of the weather, are, to a great 884 PHYSIOGRAPHY. CLASS n. extent, converted into a tissue of crystals of the present species, while the outside is covered with chloride of copper, sometimes crystallized. 5. The varieties of the present species, wherever they occur in considerable quantity, are highly valuable as ores of copper. GENUS IV. TIN-ORE. 1. PYRAMIDAL TIN-ORE. Pyramidal Tin-Ore. JAM. Syst. Vol. III. p. 155. Man. p. 238. Oxide of Tin. PHILL. p. 250. Kornisch Zinerz. Zinstein. WEEK. Hoffin. H. B. IV. 1. S. 53. 56. JZinnstein. HAUSM. I. S. 314. .Zinnerz. LEONH. S. 218. Etain oxyde. HAUY. Traite, T. IV. p. 137. Tabl. comp. p. 101. Traite', 2de Ed. T. IV. p. 152. PHILLIPS. Trans. Geol. Soc. Vol. II. p. 336. Fundamental form. Isosceles four-sided pyramid. P == 133" 26', 67° 59'. Vol. I. Fig. 8. R. G. a = tj 0-4547. Simple forms. P — oo (i) ; P (P) ; P + 1 (» = 121° 35', 87° 17 ; P + oo (/) ; [P + oo] (g) ; (P)* (z) - 159° 6', 118° 16, 135°1T ; (P + oo)3 = 126a 62' 12", 143° 7' 48"; (P + ao)5 (r) = 11 2° 37' 12", 157° 22' 48". Char, of Comb. Pyramidal. Combinations. 1. P + 1. P -f oo. Cornwall. 2. P + 1. P + oo. [P + oo]. Fig. 101; the prisms very short, Goshen, Massachusetts. S. P. P+l. P+ CD. [P+ cc]. Fig. 102. Cornwall. 4. P. P -f 1. (P)5. [P + oo]. Cornwall. 5. P — oo. P. P + l. P + oo. [P + oo]. Ehrenfriedersdorf, Saxony. ORDER Yin. PYRAMIDAL TIN-ORE. 6. P. P + 1. (P)5. [P + oo]. (P + oo)5. Fig. 103. Cornwall. Cleavage, P 4- oo and [P -f- oo] not very distinct, traces of P. Fracture imperfect conchoidal, uneven. Surface, P — QD rough, [P -f- oo] of- ten uneven ; P -f 1 sometimes irregularly striat- ed parallel to the edges of combination with P, and the latter pyramid parallel to those with P -+• 1. The prisms are sometimes vertically streaked. Lustre adamantine. Colour various shades of white, grey, yellow, red, brown, black. Streak pale grey, in some varieties it is pale brown. Semi- transparent, sometimes almost transparent ... nearly opake. Brittle. Hardness = 6-0 . . . 7-0. Sp. Gr. = 6-960, a crystallised variety; =6-519, thin columnar composition. Compound Varieties. Twin-crystals: Axis of revolution perpendicular, face of composition par- allel to one, or sometimes to several faces of P. Small reniform, rarely botryoidal shapes : original surface rough, composition very thin columnar, di- vergent from common centres, strongly connected, and often forming a second curved lamellar com- position. Massive : composition granular, sometimes almost impalpable, strongly connected, fracture un- even. The hardness of very thin columnar com- positions is often found as low as 5'5, owing prob- VOL. II. 2 B 38G PHYSIOGRAPHY. CLASS n. ably to the delicacy of the individuals in this com- position. OBSERVATIONS. 1. According to the same principles which require us' to consider Red Hematite or fibrous Red Iron-Ore, as a varie- ty of rhombohedral Iron-ore, we must also unite within one and the same species, the Wood-tin of Cornish miners, with the rest of the varieties of pyramidal Tin-ore. The distinction of the two species, Tin-stone and Cornish Tin- Ore in the Wernerian system, rests only npon the state of mechanical composition, and must therefore be abandoned, as has been already done by several mineralogists. 2. The following ingredients were found by KLAFROTII in a simple variety, by DESCOTILS in a compound one : Oxide of Tin 99-00 95-00. Oxide of Iron 0-25 5-00. Silica 0-75 0-00. In its greatest purity it contains nothing but oxide of tin, Sn, composed of 78-67 metal, and 21-33 oxygen. Alone it does not melt before the blowpipe ; but is reducible when in contact with charcoal. It is insoluble in acids. 3. This ore occurs disseminated in rocks, particularly in granite, also in beds and veins, and in those large irregu- lar masses called Stockwcrke. It is frequently accom- panied by prismatic Scheelium-ore and pyramidal Schee- lium-baryte, rhombohedral Molybdena-glance, also by rhombohedral Quartz and other species. It occurs in pebbles, and is extracted in this shape from stream-works. The varieties called Wood-tin have been hitherto found only in these repositories. 4. There are but few countries in which the present spe- cies is met with in any notable quantities. These are Saxony, Bohemia, Cornwall in Europe, and the peninsula of Malacca and the island of Banca in Asia. Small quan- tities occur in Galicia in Spain, in the department of Haute Vienne in France, and in the mountain chains called the OHDEH vin. PRISMATIC SCHEELIUM-OKE. 887 Fichtel and Riesengebiirge in Germany. Disseminated through the rocks, it is found at Zinnwald in Bohemia and Saxony and in Cornwall, in beds in granite at Zinnwald, in mica-slate in Galicia, in the Stockwerke it is found at Schlaggenwald in Bohemia, at Altenberg, Geyer, &c. in Saxony, in veins at Ehrenfrieclersdcrrf, Marienberg, Ahen- berg, and other places in Saxony, in Bohemia, but particu- larly in great prefuskm in Cornwall. Tin stream-works are likewise opened in Saxony, and still more so in Corn* wall. The columnar compositions of pyramidal Tin-ore from Mexico and ChiH, are also products of stream-works! The finest and most re'markable simple varieties are found in Cornwall, twins and regular compositions in general in Saxony and Bohemia. Small groupes of black twin-crystals have been lately discovered in the' albite-rock of Chester- field in Massachusetts, and are accompanied by red and green varieties of rhombohedral Tourmaline. 5. The pyramidal Tin-ore is' used for extracting, tin-. GENUS V. SCHEELIUM-ORE/ 1. PRISMATIC SCHEELIUM-OEE. Prismatic Wolfram. JAM. Syst. Vol. III. p. 170. Man.- p. 240. Wolfram. Tungstate of Iron. PHILL. p. 255. Wolfram. WERN. Hoffm. H. #. IV. 1. S. 242. Wolf- ram. HAUSM. I. S. 308. Wolfram. LEONH. S. 377. Sche'elin ferrugine'. HAUY. Traite, T. IV. p. 314* Tabl. comp. p. 118. Traite', 2de Ed. T. IV. p. 366. Fundamental form. Scalene four-sided pyramid. P = | ll^p | } , 105* 49r, 105° 49^ Inclination in the plane of the short diagonal = 0. Vol. 1. Fig. 41. HAUY. a : b : c : d = 1 : Jl'333 : 1:0. 388 PHYSIOGRAPHY. CLASS ir. P f 11*7° 2' ) Simple forms, i -« = {117° 2')' ^ 4- oo (r) = 98° 12'; ^! (5) ; (Pr + oo)3 = 133° KX ; ?r (w) = 98° 12'; Pr + oo (T) * Char, of Comb. Henri-prismatic. pr _ i Combinations. 1. __ ___ P + oo. Fig. 44. Ehren- . friedersdorf. Saxony. fc ^L'Tli. ?r+ oo. Pr+ oo. Fig. 46. Cornwall. Sg 3. £^Tli — iL^i. fr. P + QD. Pr+oo. 2 2 Fig. 49. 2^innwald, Bohemia. 4. 5.1-1 Z. (^)!. P, - I. P + oo. 2 2 2 2 (Pr + oo)5. Pr + QD. Zinnwald. Cleavage, Pr + oo, perfect. Fracture uneven. Surface, streaked parallel to the axis ; the rest pr _ | of the forms smooth, _ _ often curved. 2 Lustre metallic adamantine, or imperfect metallic. * Mr PHILLIPS gives the following angles: = 117° 451*, incidence of ^—— on P— 03 = 152° 40'; on Pr + co = 117022', P + co = 101° 5', the inclination of P . — co on P + co being = 90°. H. ORDER VIII. PRISMATIC SCHEELIUM-ORE. 389 Colour dark greyish- or brownish-black. Streak dark reddish-brown. Opake. Not very brittle. Hardness = 5-0 ... 5-5. Sp. Gr. = 7-155, of a crystallised variety from Zinnwald. Compound Varieties. Twin-crystals: 1. Face of composition parallel, axis of revolution perpendi- cular to Pr -f oo ; £ Face of composition parallel, axis of revolution perpendicular to a face of ?r. There is often a curious composition in the interior of crystals parallel to all their faces. Massive : com- position irregularly lamellar, easily separated, faces of composition irregularly streaked ; also columnar, the individuals being generally of a considerable size, straight and divergent, and often rather strong- ly coherent. Pseudomorphoses in the shape of py- ramidal Scheelium-baryte. OBSERVATIONS. 1. According to BERZELIUS, the varieties of the present species consist of Tungstic Acid 78'77- Protoxide of Manganese 6-22. Protoxide of Iron 1 8-32. Silica 1-25. When pure it is expressed by Mn W2 + 3 Fe W2, and the proportion of its ingredients = 77*27 ' 5*84 : 16-89. It decrepitates before the blowpipe, but may be melted in a sufficiently elevated temperature into a globule, having its surface covered with crystals possessing a metallic lustre. It is pretty easily soluble in borax. 2. This ore occurs very frequently along with pyramidal Tin-ore, in veins and beds. It is met with, however, also 390 FHYSIOGUAPUV. CLASS H.- without the Tin-ore, in veins traversing greywacjce with ores of lead, rhombohedral Quartz, Sec. 3. It occurs almost in every one of the Saxon and Bohe- mian tin-mines, as at Schlaggenwald, Zinnwald, Ehren- friedersdorf, and Geyer ; also in many places in Cornwall. It is thus likewise found in France. In the principality of Anhalt it occurs in veins in grey wacke. In the island of Rona, one of the Hebrides, it was discovered in a vein of graphic granite in gneiss. It is found in Siberia, accom- panying rhombohedral Emerald, and in the United States of North I. TANTALUM-ORE. 1. PRISMATIC TANTALUM-OBE. Prismatic Tantalum-Qre. JAM. Syst. Vol. III. p. 147. Man. p. 241. Columbite. PHILL. p. 269. Tantalit. BREITH. Hoffm. H. B. IV. 2. S. 191. Tantalit. HAUSM. I. S. 310. Tantalit. LEONH. S. 379. Tantale oxidd HAUY. Tabl. comp. p. 120. Trait;*, 2de Ed. T. IV. p. 387. Fundamental form. Scalene four-sided pyramid. P = 145° 8', 99° S', 919 12'. Vol. I. Fig. 9. LEONH. a : b : c = 1 : V 5-4545 : *J 1-1636. Simple forms. P — oo ; P ; (?r + x) 5 = 46° 5(X ; Pr — 1 = 56° 4V; £r + QD ; Pr + oo. Char, of Comb. Prismatic. Combinations. 1. P — GO. P r -f- oo. Pr -|- QD. Bodenmais, Bavaria. 2. P — oo. P. ?r— -1. (P+oo)5. Pr-f-x. Pr -f- oo. Bodenmais. Cleavage, ?r -f GO rather perfect, Pr -J- GO less dis- tinct. Traces of P — oo. Fracture imperfect ORDER vin. PKISMATIC TANTALUM-OKE. 391 conchoidal, uneven. Surface, Pr + oo vertically streaked. Lustre imperfect metallic. Colour greyish- and brownish-black. Streak dark brownish-black, on the file a little shining. Opake. Brittle. Hardness = 6-0. Sp. Gr. = 6 038. Compound Varieties. Massive : composition gra- nular. OBSERVATIONS. 1. The synonymes quoted above refer also to all those minerals which have been hitherto indiscriminately desig- nated by the names of Tantalite^ Columbite, Tantate ojcide, &c; and which occur in other localities than Bodenmais in Bavaria. Several of these varieties, however, differ so much from those included in the general description, that they cannot be all comprehended within one and the same species. Our information in regard to their regular fonns is still very defective ; it is not certain, whether the variety from Skogbohle in the parish of Kimito in Finland, possesses prismatic or hemi-prismatic forms. The colour of this variety is brownish-black, the streak between hair- brown and clove-brown, hardness = 6-0, and sp. gr. = 7*075. Of another variety, having a degree of hardness = 6*0, and a specific gravity between 7*8 and 8-0, the forms seem to be hemi-prismatic. The Tantalite from Broddbo, which agrees very nearly with that from Finbo, both in Sweden, is described as having a black colour, brown streak, a speci- fic gravity of 6-291, when purified as much as possible, and other properties which coincide with those of prismatic Tantalum-ore. It is probable that some of these varieties will form in future, one, or even several species, distinct from that to which the above description refers ; but it would be impossible, from the little we know of their natu- ral-historical properties, to decide whether these will be comprehended within the genus Tantalum-ore, or whether 892 PHYSIOGRAPHY. CLASS 11 they will perhaps form new genera. The description has been drawn up from several not crystallised varieties from Bodenmais, and the ratios of the axes of the crystalline forms are those given by LEONHAJID. 2. According to VOGEL and Count BORKOWSKY, the prismatic Tantalum-ore from Bodenmais, consists of Oxide of Tantalum 75-00 74-00. Oxide of Tin 1-00 0-40. Oxide of Iron 17'00 20-00. Oxide of Manganese 5-00 4-60. Its chemical formula is Mn2 Ta + 3 Fe2 T. Upon char- coal it suffers no change before the blowpipe, but it melts with borax, and is partly soluble in heated sulphuric acid. The Tantalite from Broddbo consists, according to BER- ZELIUS, of Oxide of Tantalum 67-586. Oxide of Manganese 5-902. Oxide of Iron 7'560. Lime 1-504. Oxide of Scheelium 8-690. Oxide of Tin 8-750. The two last of these ingredients BERZELIUS considers as accidental. It is likewise unchanged by itself before the blowpipe, and is slowly but perfectly soluble in borax. 3. Prismatic Tantalum-ore is found at Bodenmais in Bavaria, with rhombohedral Emerald, pyramidal Euchlore- mica, rhombohedral Quartz, &c., and is said to occur there in very large and distinct crystals. The variety from Had- dam in Connecticut, where it is accompanied by prismatic Corundum, &c., likewise belongs to the present species. The other varieties occur at Finbo and Broddbo near Fah- lun in Sweden, with prismatic Topaz, Albite, and rhombo- hedral Quartz. In several other places in Sweden and in Finland, it is imbedded in granite. ORDER VIII. UNCLEAVABLE UKANIUM-ORE. 393 GENUS VII. URANIUM-ORE. 1. UXCLEAVABLE URANIUM-ORE. Indivisible Uranium or Pitch-Ore. JAM. Svst. Vol. III. p. 178. Uncleavable Uranium-Ore. Man. p. 241. Uran-Ochre. Pitch-blende. PHILL. p. 2(»7- Pecherz (Uranpecherz). WERN. Hoffm. H. B. IV. 1. S. 271. Pechuran. HAUSM. I. S. 325. Uran-Pecherz. LEOXH. S. 308. Urane oxydule'. HAU Y. Traite', T. IV. p. 280. Tabl. comp. p. 113. Traite', 2de Ed. T. IV. p. 316. Regular forms and cleavage unknown. Fracture conchoidal, uneven. Lustre imperfect metallic. Colour greyish-black, inclining sometimes to iron-black, also to green- ish- and brownish-black. Streak black, a little shining. Opake. Brittle. Hardness = 5-5. Sp. Gr. = 6-468. Compound Varieties. Reniform : composition columnar, impalpable ; aggregated into a second curved lamellar composition, the faces of composi- tion being smooth and shining. Massive : compo- sition granular, individuals not distinguishable. OBSERVATIONS. 1. The analysis of a variety of the present species yield- ed to KLAPROTH, Protoxide of Uranium 86-50. Protoxide of Iron 2-50. Silica 5-00. Sulphuret of Lead 6-00. Alone it is infusible before the blowpipe, but it melts with borax into a grey scoria. If reduced to powder, it is slow- ly soluble in nitric acid. 2. The uncleavable Uranium-ore chiefly occurs in silver PHYSIOGRAPHY. CLASS n. veins, and is accompanied by various ores of silver and lead, and often intimately mixed with pyramidal Copper- py rites and hexahedral Lead -glance. Also rhombohedral and macrotypous Lime-haloide and pyramidal Euchlore- mica occur along with it. 3. Its chief localities are Johanngeorgenstadt, Marien- berg, Annaberg and Schneeberg in Saxony, and Joachims- thai and Fribus in Bohemia. In Cornwall it has been found in the tin-mines of Tincroft and Tolcarn near Ited- ruth. 4. It is used in painting upon porcelain, and yields a fine orange colour in the enamelling fire, and a black one in that in which the pprcelain itself is baked. GENUS VIII. CERIUM.ORE. 1. UNCLEAVABLE CERIUM-ORE. Indivisible Cerium-Ore, or Cerite. JAM. Syst. Vol. III. p. 183. Uncleavable Cerium-Ore. Man. p. 241. Cer- ite. PHILL. p. 263. Cerinstein. WERN. Hoff'm. H. B. IV. 1. S. 286. Cerent. HAUSM. S. 303. Cererit. LEONH. S. 388. Cerium oxyde silicifere. HAUY. Tabl. comp. p. 120. Cerium oxide' siliceux rouge. Traite, 2de Ed. T. IV. p. 393. Regular forms and cleavage unknown. Lustre adamantine. Colour, intermediate between clove-brown and cherry-red, passing into grey. Streak white. Translucent on the edges. Brittle. Hardness = 5-5. Sp. Gr. = 4-912. Compound Varieties. Massive : composition gra- nular, individuals not distinguishable ; fracture un- even and splintery. OBSERVATIONS. 1. According to HISIKGER, it consists of OS.DEH VIII. UNCLEAVABLE CERIUM-ORE. 395 Oxide of Cerium 68-69. Silica 18-00. , Oxide of Iron 2-00. Lime 1-25. Water and Carbonic Acid 9-60. Alone it is infusible before the blowpipe, but forms with borax an orange-yellow globule, which becomes paler on cool- ing. This rare mineral occurs in a bed in gneiss, at the copper mine of Nya Bastnaes near Riddarhyttan in West- manland in Sweden. It is accompanied by prismatic Bis- nmth-glance, rhombohedral Talc-mica, &c. 2. Among the minerals which accompany the uncleavable Cerium-ore, there exists still another mineral belonging to the order Ore, but which is too imperfectly known to allow of being received in the system. It is the Cerine of BERZELIUS (Cerium oxide sUiceux noir. HAUY. Traite*, 2de Ed. T. IV. p. 395.). Its forms seem to belong to the prismatic system, its cleavage being pretty distinct in a longitudinal direction. Its colour is brownish-black, streak yellowish-grey inclining to brown ; hardness = 5-5 ... 6-0; sp. gr. = 4-173. According to HISINGER, it consists of Silica 30-17, Alumina 11-31. Lime 9*12. Oxide of Cerium 28-19. Oxide of Iron 20-72. Copper (accidental) 0*87. Volatile ingredients 0-40. Before the blowpipe it froths and melts easily into an opake, shining, black globule, which acts upon the magnetic needle. Also with borax it melts easily, and forms a reddish- or yel- lowish-brown ; with a small proportion of soda, a dark greenish-grey globule. It agrees very nearly in several of its properties with Allanitc. 396 PHYSIOGRAPHY. CLASS II. GENUS IX. CHROME-ORE. 1. OCTAHEDRAL CHROME-ORE. Prismatic Chrome-Ore. JAM. Syst. Vol. III. p. 185. Prismatic Chrome-Ore or Chromate of Iron. Man. p. 243. Chromate of Iron. PHILL. p. 240. Chromeisenstein. WEEN. Hoffm. H. B. III. 2. S. 226. Chromeisenstein. HAUSM. I. S. 252. Eisenchrom. LEONH. S. 354. Fer chromate'. HAUY. Traite', T.IV. p. 129. TabLcomp. p. 99. Traite', 2de Ed. T. IV. p. 130. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple form. 6, Vol. I. Fig. 2. St Domingo. Fracture uneven, imperfect conchoidal. Lustre imperfect metallic. Colour between iron- black and brownish- black. Streak brown. Opake. Brittle. Hardness z= 5-5. Sp. Gr. = 4498, a variety from Stiria. Compound Varieties. Massive : composition gra- nular, the individuals being of various sizes, and generally firmly connected; they are often enve- loped in a talcose stratum. OBSERVATIONS. 1. The octahedral Chrome-ore consists, according to VAU- QUELIN and KLAPROTH, of Oxide of Chrome 43-00 55-50. Protoxide of Iron 34-70 33-00. Alumina 20-30 6-00. Silica 2-00 2-00. Alone it is infusible before the blowpipe, but acts upon the magnetic needle, after having been exposed to the reducing flame. It is difficultly but entirely soluble in borax, and imparts to it a beautiful green colour. 2. The varieties of the present species frequently occur in ORDER VIII. AXOTOMOUS IRON-ORE. 397 a compound state. The hexahedral crystals from Stiria, occasionally combined with the octahedron, and which have been considered as belonging to it, are in fact octa- hedral Iron-ore. But crystals in the form of regular octa- hedrons are quoted from Hoboken in New Jersey, and from the Bare-hills near Baltimore in Maryland. This is also the form in which the Chrome-ore occurs in St Do- mingo, and in Shetland. The Stiriau has not yet been found crystallised, but there are indications of cleavage or composition in its interior apparently in only one direction, which deserve very well the attention of mineralogists. The varieties of the present species have been hitherto found only in serpentine, in irregular veins and beds, which seem to be of contemporaneous formation with the rock itself. 3. The first varieties of octahedral Chrome-ore were dis- covered in the department du Var in France, where they form nodules and kidney-shaped masses. In Stiria it occurs in the Gulsen mountain near Kraubat, in serpentine in very irregular veins, traversing the rock in all pos- sible directions. It is found also near Portsoy in BanfF- shire, and at Buchanan in Stirlingshire, in Scotland, in the latter place imbedded in limestone. It is met with in large masses in the Shetland isles, Unst and Fetlar, in the Bare-hills near Baltimore, and in the Uralian moun- tains. At Hoboken in New Jersey, octahedral crystals of it are imbedded, both in serpentine and in limestone. It has also been met with in Silesia and in Bohemia. 4. The octahedral Chrome-ore is a highly valuable mine- ral for extracting the oxide of chrome, which is employed either alone or in various combinations with the oxides of other metals, as cobalt, lead, mercury, &c. both for paint- ing on porcelain, and for painting in oil. It yields green, yellow, and red pigments. GENUS X. IRON-ORE. 1. AXOTOMOUS IRON-ORE. Titanitic Iron, from Gastein in Salzburg. 398 PHYSIOGRAPHY. CLAM II. Fundamental form. R =85*5^. Vol. I. Fig. 7. R. G. a =. J 5-6. Simple forms. R— co (a) ; | R — 2 = 127° 4(X ; R — 1 (C) = 115° 8' ; R (JR) ; R + 1 (d) = 68° 42' ; P + I (b) - 128° 1', 122* 28'. Char, of Comb. Hemi-rhombohedral with parallel faces. Z±i = 91° 2(X. Combinations. 1. R — oo. R. t^4 Fig. 141. 142. 2. R — QD. fR — 2. R — 1. R. ?±I. 3. R — x. R — 1. R. ^-\ R+l. Fig. 144. Irregular forms, grains. Cleavage, perfect parallel to R — • oo, less distinct R, not always observable. Fracture conchoidal. Surface, R — 1 streaked parallel to its edges of combination with R — CD ; the other faces gene- rally more rough than smooth, and all of them alike. Lustre imperfect metallic. Colour dark iron-black. Streak black. Opake. Brittle. Hardness = 5-0 ... 5*5. Sp. Gr. = 4-661. Compound Varieties. Twin-crystals : axis of re- volution perpendicular, face of composition parallel to R — GO, Fig. 143. The compositions of this kind, as hitherto observed, are not quite regularly formed, but consist generally of several alternating laminae. The situation of the individuals is, how- ever, recognizable from the direction of their faces. ORDEE Tin. , OCTAHEDRAL IRON-OBE. 399 OBSERVATION'S. 1. The chemical composition of axotomous Iron-ore has not been exactly ascertained. It is likely to consist of the oxides of iron and titanium. 2. It occurs in imbedded crystals and grains in several varieties of prismatic Talc-mica, and macrotypous Lime- haloide, in the valley of Gastein in Salzburg, and frequent- ly along with the crystals of peritomous Titanium-ore, over which it often forms a black coating, as at Klattau in Bo- hemia, in the gold stream-works at Ohlapian in Transylva- nia, &c. 3. The mineral most nearly resembling axotomous Iron- ore, if we compare the descriptions published, is the Crich- toniie of Count BouRNOir (Fer oxidnle tltani. HAUY. Traite', 2de Ed. T. IV. p. 98), at least, as to the general nature of its forms, and the other properties, which, how- ever, are not ascertained in the Crichtonite with sufficient accuracy. According to Count BOURNON, the primitive form of this substance is an acute rhombohedron, whose plane angle at the apex is = 18°. The Abbe' HAUY from this observation deduces the ratio of the diagonals = */ 40 : 1, from which the axis follows = x/267'75, and the ter- minal edge = 60° 50'. Its most common crystalline forms are combinations of this rhombohedron with II — os, similar to Fig. 113., or also flat twelve-sided prisms, which have never been accurately described. Its only locality is the department of the Isere in France, where it occurs in nar- row veins along with pyramidal Titanium-ore. It consists, according to BERZELIUS, of oxide of iron and oxide of ti- tanium. 2. OCTAHEDRAL IRON-OttE. Octahedral Iron-Ore. JAM. Syst. Vol. III. p. 188. Man. p. 244. Oxydulated Iron. PHILL. p. 221. Magnet- eisenstein. WERV. Hoffm. H. B. III. 2. S. 216. Mag- neteisenstein. HAUSM. I. S. 245. Magneteisensteio- 400 PHYSIOGRAPHY. CLASS it. LEONH. S. 349. Fer oxydute. HAUY. Traite, T. IV. p. 10. Tabl. comp. p. 93. Traite, 2de Ed. T. III. p. 560. Fundamental form. Hexahedron. Vol. I. Fig. 1. * • Simple forms. H, Gulsen, Stiria ; O (P), Vol. I., Fig. 2., Fahlun, Sweden ; D (/), Vol. I. Fig. 31., Traversella, Piedmont; A 2, Vol. I. Fig. 32.; B, Vol. I. Fig. 33., Zillerthal, Salzburg; C*, Vol. 1. Fig. 34; Ti, Vol. I. Fig. 35. Char, of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3 & 4. Gulsen. 2. O. D. Sweden. 3. H. O. D. Piedmont. 4. O.D.C a. Vesuvius. 5.O D. Az.B. Ziilerthal. 6. O. D. Aa. C«. Ti. Zillerthal. Irregular forms, grains. Cleavage, octahedron, in some varieties perfect and easily obtained, in others entirely obliterated by conchoidal fracture. Fracture conchoidal, un- even. Surface, the dodecahedrons commonly streaked parallel to their edges of combination with the octahedron ; of the octahedral trigonal- icositetrahedron smooth, though curved ; the sur- face of all the other forms is smooth. Lustre metallic, in some varieties imperfect. Co- lour iron-black. Streak black. Opake. Brittle. Hardness = 5-5 ... 6-5. Sp. Gr. = 5-094, octahedrons imbedded in chlorite. Compound Varieties. Twin-crystals : axis of re- volution perpendicular, face of composition parallel to a face of the octahedron, Fig. 156. Massive : ORDER VIII. OCTAHEDRAL IRON-ORE. 401 composition granular, of various sizes of individuals, and different degrees of cohesion. If the composi- tion be almost impalpable, fracture becomes flat conchoidal, even or uneven. OBSERVATIONS. 1. The present species used to be divided into Common Magnetic Iron-Ore, and Granular Magnetic Iron-Ore or Iron- Sand. The first of these contains almost the whole of what is comprised within the species, except small octahedral crystals and grains, which occur either solitary in sand, or imbedded in basalt, and will be taken more particular no- tice of afterwards. 2. HISINGER obtained from a variety of the present species Protoxide of Iron 94-38. Magnesia 0-16. The loss is oxygen, as the mineral contains both protoxide and peroxide of iron, according to BERZELIUS, in the pro- portion of 30-98 to 69-02, expressed by Fe + 2 Fe ; the whole content of oxygen being 28-215. It is infusible be- fore the blowpipe, but assumes a brown colour and loses its attractory power, after having been exposed to a great heat. It is soluble in heated muriatic acid, but not in nitric acid. It may be obtained crystallised, by fusing it ; and crystals are b'kewise often produced in the process of roasting the ore which contains this mineral. 3. The octahedral Iron-ore occurs always in beds, which are sometimes uncommonly extended, both in length and thick- ness, or imbedded in crystals and grains, in chlorite slate, serpentine, greenstone, &c. The beds are included chiefly in gneiss, mica-slate, clay-slate, hornblende-slate, and chlo- rite-slate, greenstone, or sometimes limestone. It is ac- companied by various species of the genera Augite-spar, Feld-spar, Lime-haloide, &c. also by dodecahedral Garnet, rhornbohedral Quartz, rhombohedral Iron-ore, and other species. Those remarkable and extensive beds in the Ban- VOL. II. 2 C 402 PHYSIOGRAPHY. CLASS n. nat, which contain so much of copper-ore at Moldawa, Saska, Orawitza, &c. consist in a more northerly direction, at Dognatzka, almost entirely of the present species. 4. Large masses of octahedral Iron-ore are found at Arendal in Norway, the Taberg in Smaland in Sweden, and Chili ; also in North America. It occurs at Berggiess- hiibel and Schmalzgrube in Saxony, at Presnitz in Bohe- mia, in the Schmalenberg in the Hartz ; near the Abbey of Pella in Stiria, along with rhombohedral Iron-ore, at Kahlwang with granular limestone, and in many other places along the chain of the Alps. It is likewise met with in Corsica, in Unst, one of the Shetland isles, in Russia, Silesia, &c. Imbedded crystals are very frequent ; among these the rare hexahedron occurs in the Gulsen mountain near Kraubat in Stiria. Well defined crystals occur at Ve- suvius, and Traversella in Piedmont. 5. The present species is one of the most important ores of iron, and large quantities of that metal are annually ex- tracted from it in Sweden, Norway, Russia, and other countries. 6. It is highly probable that the Iron-Sand will be esta- blished in future into a particular species. Its specific gra- vity never exceeds 4-9, it was found = 4-871 in perfectly pure grains, while that of cleavable varieties of octahedral Iron-ore never is below 5-0. Also several other properties indicate such a difference, as the distinct imperfect metallic lustre, even a slight difference of colour, and the entire want of regular forms, as it cannot be said with perfect se- curity whether the octahedrons quoted, really belong to the present species. According to CORDIER, it consists of Protoxide of Iron 79-20. Oxide of Titanium 14-80. Oxide of Manganese 1-60. Alumina 0-80. It occurs in the Bohemian Mittelgeburge, in the moun- tains of the Rhon, at Andernach on the Rhine ; also in ORDER viri. DODECAIIEDRAL IRON-ORE. 403 France, in Pomerania, and other countries, sometimes in sufficient quantity for melting. 3. DODECAHEDRAL IRON-ORE. Frank-Unite. PHILL. p. 226. Franklinit. LEONH. S. 313. Fundamental form. Hexahedron, Vol. I. Fig. 1. Simple forms. 6, Vol. I. Fig. 2. ; D, Vol. I. Fig. 31.; B, Vol. I. Fig. 33. Char, of Comb. Tessular. Combinations. 1. O. D. & O. B. B. Sim. Fig* 155., without the faces marked P. Irregular forms, grains. Cleavage, octahedron very indistinct. Fracture conchoidal. Surface of all the forms smooth. Lustre metallic. Colour iron-black. Streak dark brown. Opake. Brittle. Acts upon the magnetic needle, but does not exhibit magnetic poles. Hardness = 60 . . . 6-5. Sp. Gr. = 5-091. Compound Varieties. Massive : composition granular, strongly connected. OBSERVATIONS. 1. The dodecahedral Iron-ore consists, according to BER- THIER, of Peroxide of Iron 66-00. Oxide of Zinc 17-00. Red Oxide of Manganese 16-00. Its composition is expressed in the formula Zn + Mn + 4 Fe, which corresponds to 17'2 oxide of zinc, 15-7 oxide of manganese, and 67-1 peroxide of iron. It is soluble without 404 PHYSIOGRAPHY. CLASS n. effervescence in heated muriatic acid. In a high degree of temperature the zinc is driven off, and a hard compound of iron and manganese remains. 2. The dodecahedral Iron-ore is found imbedded in pris- matic Zinc-ore and rhombohedral Lime-haloide in several mines in Sussex county, New Jersey, in North America. Those crystals which present the most distinct forms, are imbedded in the prismatic Zinc-ore, and not those in the Lime-haloide. But already these exhibit rounded faces on the solid angles of the octahedron, which, being enlarged, are the only ones remaining in the irregular grains imbed- ded in the rhombohedral Lime-haloide. 4. RHOMBOHEDRAL IRON-ORE. Rhomboidal Iron-Ore. JAM. Syst. Vol. III. p. 199. Man. p. 245. Specular Iron. Red Iron-Ore. PHILL. p. 224. 228. Eisenglanz. Rotheisenstein. Thoneisenstein (in part). WERN. Hoffm. H. B. III. 2. S. 229. 239. 274. Blutstein. HAUSM. I. S. 256. Eisenoxyd. LEOXH. S. 336. Fer oligiste. Fer oxyde' (in part). HAU Y. Traite', T. IV. p. 38. 104. Fer oligiste. Tabl. comp. p. 94. Traite, 2de Ed. T. IV. p. 5. Fundamental form. Rhombohedron. R = 85° 58'. Vol. I. Fig. 7. a = V 5-6041. Simple forms. R — oo (o) ; R — 4- = 1 70° 15' ; R — S (y) = 160° 42'; R — 2 (*) = 142° 56'; R — 1 = 115° 7 ; R (P) ; R + 1 (fc) = 68° 42' ; R + oo (r) ; P + 1 (n) = 128° (X, 122° 29'; f P + 3 = 121° 5', 159° 16'; P + oo (z) ; (P _ g)5 (^) — 117° 58', 139° 49', 118° 21'. Char, of Comb. Rhombohedral. Combinations. 1. R — oo. R. Sim. Fig. 111. and Fig. 119. Vesuvius. ORDER VIII. RHOMBOHEDKAL IRON-ORE. 405 2. R — 2. R. Elba. 3. R — • oo. P -f- 1 . Framont, Lorraine. 4. R — -x. R. P + 1. Sim. Fig. 143. Alten- berg, Saxony. 5. R — 2. R. P + 1. Fig. 124. Elba. 6. R — 3. R — 2. R — 1. R. (P — 2)5. P+l. R + 1. i p + 3. Elba. Cleavage, R — QD. R. In some varieties scarce any traces appear, while in others it seems to be perfect, which, however, must be in a great mea- sure attributed to composition. Fracture con- choidal, uneven. Surface, those rhombohedrons which are in parallel position with R, as R — 49 R — 2, R -f oo, particularly the obtuse ones, are horizontally streaked, sometimes so deeply that they appear rounded ; R is sometimes streaked parallel to the edges of combination with P -f- 1 ; R — 3 is uneven and often curved, it is striated at the same time parallel to the edges of combi- nation with R — 2 ; R — 1 is sometimes curved but always smooth. Lustre metallic. Colour dark steel-grey, iron-black. Streak cherry-red, reddish-brown. Surface fre- quently tarnished ; generally with the exception of R — oo, which may be useful to beginners in finding the true position of the crystals. Opake; very thin laminae are faintly translucent, and shew a deep blood-red colour. Brittle. Sometimes feeble action upon the magne 406 PHYSIOGRAPHY. CLASS n. tic needle. Hardness = 5-5 ... 65. Sp. Gr. = 5-251, a crystalline variety from Sweden. Compound Varieties. Twin-crystals: 1. Axis of revolution perpendicular, face of composition par- allel to It — GO ; the individuals are continued be- yond the face of composition (Altenherg, Saxony). Sometimes two individuals in the same position are joined in a face of li -f- oo, and terminate at this face (Stromboli). 2. Axis of revolution perpendi- cular, face of composition parallel to a i'ace of R, generally observable in the reversed situation of thin films engaged in the mass (Elba). Faces of composition in these directions must not be con- founded with faces of cleavage. Globular, reniform, botryoidal, and stalactitic shapes : surface generally smooth, composition more or less thin columnar, sometimes even impalpable ; in this case the lustre becomes imperfect metallic, and the colour red; fracture of impalpable compound va- rieties even, flat conchoidal, or uneven. Compound varieties often join in a second and third composi- tion, which are curved lamellar and granular ; the junction of granular masses produces frequently very smooth faces, while the reniform surface of the curved lamellar compositions is rough, and more difficultly obtained by separating the par- ticles than the first. Massive: composition, 1. Co- lumnar, generally imperfect, thick, and diverging from common centres. 2. Granular, and often ORDER VIII. RHOMBOHEDRAL IRON-DUE. 407 impalpable, sometimes very distinct and easily se- parated ; often, however, they are strongly cohe- rent ; if they are impalpable, their lustre decreases, their colour becomes red, and the fracture even, uneven, or flat conchoidal. 3. Lamellar, joined in the face of R — oo, thick and variously bent ; sometimes, however, they are so thin that they allow blood-red light to pass ; if they are still thinner, their colour becomes red altogether, and their lustre imperfect metallic : the faces of com- position are often irregularly streaked. When the cohesion among the particles is diminished, the la- mellar varieties become scaly and glimmering, the granular ones earthy and dull. Pseudomorphoses in the shape of rhombohedral Lime-haloide, octa- hedral Fluor-haloide, &c. OBSERVATIONS. 1. There can hardly be a more striking example of the necessity of correctly ascertaining the simple and com- pound state of a mineral, than that afforded in the species of rhombohedral Iron-ore, even in regard to the correct determination of the species itself; for the two species of Specular Iron-ore and Red Iron-ore entirely depend upon this composition. Its importance extends likewise to the determination of the genus ; for the connection between the octahedral, rhombohedral, and prismatic Iron-ore, cannot be rightly understood if we do not pay attention to the simple or compound state of their varieties. Specular Iron- Ore contains all the simple varieties and those of the com- pound ones, which have not yet lost their metallic appear- ance by the too small size of their component individuals. Those in thin lamellar compositions have been called Mi- 408 PHYSIOGRAPHY. CLASS II. caceous Specular Iron-Ore, while the rest form the Common Specular Iron-Ore. Those varieties which have lost the metallic appearance are included within the lied Iron-Ore, divided into Fibrous Red Iron-Ore or Red Hematite, which occurs in reniform and other imitative shapes, and consists of columnar particles of composition ; into Compact and Ochrey Red Iron-Ore, which are massive, and consist of impalpable granular individuals more or less firmly con- nected; and into Scaly Red Iron-ore, or Red Iron Froth, con- sisting of very small scaly lamellar particles, which in most cases are but slightly coherent. This variety is in imme- diate connexion with the micaceous specular iron-ore, and an uninterrupted transition exists between it and the crys- tallised specular iron-ore itself. Among the varieties of Clay Iron-Ore, the following may be considered as an appendix to the present species, all of which are of a red colour, but more or less impure, and mixed with earthy substances. Reddle possesses an earthy, coarse slaty fracture ; it soils and writes, and may be used as a drawing material. Jaspery Clay Iron- Ore has an even, or large and flat conchoidal fracture, and a hardness which is considerable if compared with other minerals of a similar formation. Columnar and Lenticular Clay Iron-Ore are distinguished, the first by the columnar form, the latter by the flattish granular form of its particles of composition. 2. The micaceous specular iron-ore, analysed by Bu- CHOLZ, and the red hematite, analysed by D'AUBUISSON, have been found to consist of Peroxide of Iron 100-00 90-00 ... 94-00. Oxide of Manganese 0-00 a trace. Silica . 0-00 2-00. Lime 0-00 a trace 1-00. Water 0-00 2-00 ... 3-00. Its chemical sign is Fe, the proportion of metal to that of oxygen being = 69-34 : 30-66. The clay iron-ores, being more or less mixed with earthy substances, vary in their contents, and several of their properties are dependent upon H VIII. HHOMBOHEDRAL IKOX-OKE. 409 the nature of these admixtures. Thus lenticular clay iron- ore is very rich, while the columnar variety contains but little iron, and is produced from nodules of common clay iron-stone originally engaged in common clay, which have been converted by the influence of heat from burning coal seams, the one into columnar clay iron-ore, the other into porcelain jasper. The rhombchedral Iron-ore is infusible before the blowpipe, but melts with borax, and forms a green or yellow glass, like pure oxide of iron. It is like- wise soluble in heated muriatic acid. 3. It occurs most commonly in beds and veins in ancient rocks. Clay iron-ore forms either by itself beds in secondary mountains, or it is included in beds of clay in the shape of no- dules or irregular masses. Rhombohedral Iron-ore occurs iu crystals among the rocks ejected by Vesuvius, and lining the cavities and fissures of lava, where it seems to be a product of sublimation. In beds, it is generally accompanied by other ores of iron, several species of the genera Feld-spar, Augite- spar, and Garnet ; rhomboheural Lime-haloide and rhom- bohedral Quartz ; in veins, the compound varieties are chiefly associated with several varieties of rhombohedral Quartz (such as Iron-flint, &c.), the simple ones in narrow veins in primitive mountains, likewise with rhombohedral Quartz, but moreover with prismatic Feld-spar and Albite, with ores of titanium, &c. 4. The most distinct crystals, sometimes of considerable size, are found in the island of Elba, along with hexahedral Iron-pyrites and rhombohedral Quartz ; at Framont in Lorraine ; at St Gothard in Switzerland ; in Dauphiny, where they occur in narrow veins in primitive rocks ; in the vicinity of Mount Vesuvius, and in the island of Stromboli. Besides the island of Elba, there occur considerable quantities of this species in Norway and Swe- den, in Stiria, &c. frequently mixed with octahedral Iron- ore. Micaceous Iron-ore is very common in the beds of brachy typous Parachrose-bary te in Stiria and Carinthia. Red Iron-ore is found in Saxony, Bohemia, the Kartz, the 410 PHYSIOGRAPHY. CLASS II. Fichtelgebiirge, at Ulverstone in Lancashire, and other places in England, and in many other countries. Jaspery clay iron-ore is almost entirely confined to the vicinity of Fischau and Meiersdorf near Wienerisch Neustadt in Lower Austria ; the columnar variety occurs in several localities of the north of Bohemia, in the counties of Elbogen and Leitmeritz ; the lenticular clay iron-ore forms a bed in the transition district of central Bohemia, in the counties of Pilsen, Beraun, and Itackonitz, &c. The species of rhom- bohedral Iron-ore is not a rare one, and several of its va- rieties are met with in different countries. 5. The rhombohedral Iron-ore is a mineral of the highest importance, and yields a considerable proportion of the iron annually produced in the different quarters of the globe, lied Hematite, sometimes also compact Red Iron- ore, are used for polishing metals, and Reddle as a writing material. 5. PEISMATIC IRON-OBE. Prismatic Iron-ore. JAM. Syst. Vol. III. p. 225. Man. p. 250. Hydrous Oxide of Iron. Brown Iron-ore. PHILL. p. 226. 230. Brauneisenstein (excepting Braun- eisenrahm). Thorieisenstein (in part). WERN. Hoffm. H. B. III. 2. S. 250. 274. Brauneisenstein. HAUSM. I. S. 268. Eisenoxyd-Hydrat. LEONH. S. 342. Fer oxyde' (in part). HAUY. Traite', T. IV. p. 104. Fer oxyde' (excepting Fer oxyde' carbonate'). Tabl. comp. p. 98. Traite', 2de Ed. T. IV. p. 101. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Combinations, somewhat resembling Fig. 20., but variously modified on the angles, where the py- ramids e and p occur in the figure. They are compressed between M and M9 and elongated in the direction of n. Incidence of d on d OEDER VIII. PRISMATIC IRCN-ORE. 411 = 117° 3(y, of n on M = 117° 50% according to PHILLIPS, n on n over M = 130° 14', according to BROOKE. Cleavage, pretty distinct, parallel to the broad faces of the crystals. Surface, deeply streaked in a longitudinal direction. Lustre adamantine. Colour, various brown shades, of which yellowish-brown, hair-brown, clove- brown, and blackish- brown, are the most com- mon. Streak yellowish-brown. Crystals often semi-transparent, and shewing a blood-red tint. Other varieties are nearly opake. Brittle. No action on the magnet. Hardness = 5-0 ... 5-5. Sp. Gr. = 3-922, of a columnar compound variety. Compound Varieties. Globular, reniform, stalac- titic and fruticose shapes : surface of various de- scriptions, smooth, granulated, reniform, drusy; composition columnar, individuals very delicate, often impalpable. In the latter case fracture be- comes even, flat conchoidal or uneven. The com- position is often repeated ; granular and curved la- mellar masses are formed of columnar composi- tions, the faces of composition being either smooth, or covered with reniform asperities. Massive : com- position columnar or impalpable. Sometimes the particles are so slightly coherent, that the mass ap- pears earthy and dull. Pseudomorphoscs of rhom- boheclral Lime-haloide. PHYSIOGRAPHY. CLASS n. OBSERVATIONS. 1. The division introduced among the varieties of the present species is similar to that which has been given to lied Iron-Ore. We must except, however, the Brown Iron-Froth which this division contains, since it properly does not belong to the present species. Moreover, some of what are generally considered as pseudomorphoses or supposititious crystals, must be excluded, because they are not real pseudomorphoses, consisting of compound varie- ties of this species, but decomposed varieties of three others, the hexahedral and prismatic Iron-pyrites, and the brachytypous Parachrose-baryte, to which they must be severally referred. The Fibrous Brown Iron-ore or Brown Hematite contains the real crystals and the compound va- rieties in stalactitic, reniform, and other imitative shapes, also those massive varieties in which the composition still may be ascertained. Compact Brown Iron-ore comprehends those imitative shapes and massive varieties, in which the composition is no longer observable, but which are still firmly connected ; while Ochrey Brown Iron-ore is applied to those which have an earthy texture, and are friable. As impure varieties of the species we must consider some of the clay Iron-ores, such as the Granular, the Common^ the Pisiform, and the Reniform clay iron-ore. The granular variety is composed of compact roundish or globular mass- ^ es, the reniform one of alternating coats of different colour and consistency, disposed in a reniform surface. In the pisiform variety we meet with a similar composi- tion, only in small globules, parallel to the surface of which the lamellae are disposed. The compact pisiform clay iron-ore, however, does not belong to the present species, but it is decomposed prismatic Iron-pyrites, as is demonstrated not only by the crystalline forms which it presents, and which are described in books, but likewise from the nucleus of undecomposed pyrites, which larger specimens of it often contain. ORDER Vlii. PRISMATIC IKON-ORE. 413 2. According to D'AuBuissoN, the present species con- sists of Peroxide of Iron 82-00 84-00. Water 14-00 11-00. Oxide of Manganese 2-00 2-00. Silica 1-00 2-00. It is a hydrate of peroxide of iron, 2 Fe 4- 3 Aq, the pro- portions of peroxide of iron and water being as 85 30 to 14-70. The first analysis refers to a hematitic variety, and the second to a compact one. Before the blowpipe it be- comes black and magnetic. It melts with borax into a green or yellow glass, and is soluble in heated nitro-muria- tic acid. 3. The present species occurs in beds and veins. In the first it is very generally accompanied by brachytypous Fa- rachrose-baryte, sometimes also by prismatic Hal-baryte, rhombohedral and prismatic Lime-haloide, rhombohedral Quartz (often Calcedony), and other species. These beds are included both in ancient and in secondary rocks, the latter of which, though very thick, do not extend to a great distance. It is frequently associated with the species of the following genus, particularly where it occurs in veins. In these repositories also a crystallised variety in thin lamellae has been found, and has received the name of Rubinglimmcr or Gothite. Another variety in velvety reniform shapes oc- curs in silver-veins, with hexahedral Lead-glance, &c. Acicular crystals are met with in geodes of rhombohedral Quartz, probably formed in veins, and in agate balls. Those varieties of clay iron-stone which belong to the present species either form beds by themselves in secondary rocks, or they are imbedded in strata of clay in the shape of lar- ger or smaller globular concretions, some of them belonging to the coal measures, others to various kinds of sandstone. 4. Prismatic Iron-ore is very plentiful in some countries. It is found in beds in gneiss along with granular limestone, at Friesach, at Hiittenberg, and in the valley of Lavant in Carinthia, at Turrach and Eisenerz in Stiria ; in the last 11* PHYSIOGRAPHY. CLASS II. place, however, it is not very common. Under similar cir- cumstances it is met with at Torotzko in Transylvania, and probably also at Dobsehau, Szirk, &c. in Hungary. It likewise occurs in beds at Schneeberg in Saxony, at Kams- clorf and Saalfeld in Thuringia, partly in newer rocks. It is found in veins in various parts of Saxony, Nassau, the Hartz, &c. ; and among these are some of the finest varie- ties in imitative shapes, Gothite is found in the districts of Siegen and Sayn ; the velvety varieties at Przibram in Bohemia, several crystallized varieties, sometimes deter- minable, in the vicinity of Bristol in England, and in the lake of Onega in Russia. Granular clay iron-ore is found in Eichstadt, in Wirtemberg, in Switzerland, in Salzburg, and in the Tyrol. Rich varieties of the common clay iron- ore occur in Bohemia, in Silesia, at Wehrau in Lusatia, in Westphalia, but particularly in England and Scotland. The kidney -shaped variety is met with near Teplitz in Bo- hemia, Tarnowitz in Silesia, in Poland, in several districts of Lower Stiria, &c. The pisiform clay iron-ore is found in Swabia, Franconia, Hessia, and other countries. In some of them, however, also the compact variety is often found in caves in limestone, as at Wochein in Carniola, or also in several of the highest limestone mountains of Stiria, where it is met with in single specimens, as, for instance, upon the Reichenstein near Eisenerz. 5. The prismatic Iron-ore is by no means less important in the manufactures of cast and wrought iron, than the preceding species. The pig-iron obtained from melting its purer varieties with charcoal in particular may be easily converted into steel. 6. DI- PRISMATIC IRON-ORE. Lievrite. JAM. Syst. Vol. III. p. 539. Man. p. 324. Lievrite. Yenife. PHILL. p. 24. Lievrit. WERN. Hoffm. H. B. II. 1. S. 376. Ilvait. HAUSM. II. S. 665. Lievrit. LEONH. S. 366. Yenite. HAUY. Tabl. comp. p. 42. Fer calcareo-silieeux. Traite', 2de Ed. T. IV. p. 9 1 . ORDER vin. DI-miSMATIC IRON-ORE. 415 Fundamental form. Scalene four-sided pyramid. P = 139° 37', 117° 38', 77° 16'. Vol. T. Fig. 9. HAUY. a : b : c = 1 : V5'1428 : ^2-2857. Simple forms. P — QD ; P (o) ; P + o> (M) = 112° 37'; (Pr + oo)3 = 78° 28'; Pr (P) — 113° 2'; ?r + oo. Char, of Comb. Prismatic. Combinations. 1. P. P -f- QD. 2. Pr. P + oo. 3. Pr. P. P 4- oo. Fig. 4. 4. Pr. P. P -f oo. (?r + QD)5. All of them from Elba. Cleavage, Pr and P + oo indistinct, more easily observed P — oo and Pr 4- oo. Fracture im- perfect eonchoidal, uneven. Surface streaked, of the vertical prisms parallel to the axis, of the rest of the faces very frequently parallel to the edges of combination between Pr and P. Lustre imperfect metallic. Colour intermediate be- tween iron-black and dark greyish-black, passing into greenish-black. Streak black, sometimes in- clining to green or brown. Opake. Brittle. Hardness = 5-5 ... 6-0. Sp. Gr. = 3'994, a crystalline variety from Elba. Compound Varieties. Massive : composition co- lumnar, thin and straight, sometimes granular, the individuals being scarcely distinguishable. OBSERVATIONS. 1. According to DESCOTILS, the di-prispiatic Iron-ore consists of 416 PHYSIOGBAPHY. CLASS ir. Oxide of Iron 55 00. Silica 28-00. Lime 12-00. Oxide of Manganese 3-00. Alumina 0-60. After having been exposed to heat, it acts on the magnetic needle. Before the blowpipe it melts easily and without ef- fervescence into an opake glass, which is likewise magnetic. Glass of borax is coloured by it yellowish-green. It is so- luble in muriatic acid. 2. The present species is found in beds in primitive rocks, along with paratomous and prismatoidal Augite-spar, with dodecahedral Garnet, rhombohedral Quartz, octahedral Iron-ore, &c. 3. Its chief locality is the island of Elba, where it is found in crystals sometimes of considerable size ; but it has been discovered also at Kupferberg in Silesia, at I'ossam in Norway, in Siberia, and in North America. GENUS XI. MANGANESE-ORE. 1. PYRAMIDAL MAXGANESE-ORE. Foliated Black Manganese- Ore. JAM. Syst. Vol. III. p. 263. Black Manganese. PHILL. p. 381. Schwarzer Braunstein. WERN. Hoffm. H. B. IV. 1. S. 149. Bliittriger Schwarz-Braunstein. HAUSM. I. S. 293. Manganese oxyde hvdrate. HAUY. Traite', 2de Ed. T. IV. p. 2G4. Fundamental form. Isosceles four- sided pyramid. P = 105° 25', 117° 54'. Vol. I. Fig. 8. Ar. a = V2'7C. Simple forms. |P — 4 (a) = 139° 56', 58° 46'; P — 1 = 114° 51', 99° 11' ; 1* (P). Char, of Comb. Pyramidal. ORDER VIII. PYRAMIDAL MANGANESE- ORE. 417 Combinations. 1. |P — 4. P. Fig. 105. 2. |P — 4. P — 1. P. Cleavage, P — oo rather perfect ; P — 1 and P less distinct, and interrupted. Fracture uneven. Surface, f P — 4, very smooth and shining, P horizontally streaked and often dull. Lustre imperfect metallic. Colour brownish-black. Streak dark reddish- or chestnut-brown. Opake. Hardness = 5-0 ... 5-5. Sp. Gr. = 4-722, of a crystallised variety. Compound Varieties. Twin-crystals : Axis of revolution perpendicular, face of composition par- allel to a face of P — 1. Fig. 106. The com- position is often repeated parallel to all the faces of the pyramid. Fig. 107. Generally small particles only of the surrounding individuals are joined to the central one. Massive : composition granular, firmly connected. OBSERVATIONS. 1. The pyramidal Manganese-ore consists of oxide of manganese, but no analysis of it has yet been published. Perhaps the variety from Piedmont, analysed by BERZE- LIUS, which yielded oxide of manganese 75'80, silica 13-17* oxide of iron 4'14, and alumina 2-80, may belong to the present species. In the oxidating flame of the blowpipe it yields a fine amethyst coloured glass. It is soluble in heated sulphuric acid, -. , : 2. It has been found in veins in porphyry, along with other ores of manganese at Oehrenstock, near Ilmenau in Thuringia, and at Ihlefeld in the Hartz. From these lo- calities at least it seems to be a rare mineral. VOL. ii. 2 D 418 PHYSIOGRAPHY. CLASS II. 2. UNCLEAVABLE MANGANESE-ORE. Compact and fibrous Manganese-Ore or Black Hema- tite. JAM. Syst. Vol. III. p. 261. 262. Prismatic Manganese-Ore or Black Manganese-Ore (in part). Man. p. 255. Black Iron-ore (in part). Compact Grey Oxide of Manganese. PHILL. p. 232. 244. Schwarz- eisenstein. WERN. Hoffm. H. B. III. 2. S. 270. Fas- riger and dichter Schwarzbraunstein. HAUSM. I. S. 293. 294. Dichtes Schwarz-Manganerz. LEONH. S. 374. Manganese oxyde noir-brunatre ? I IAU Y. Tabl. comp. p. 110. Manganese oxyde hydrate' coneretion- nd Traite, 2de Ed. T. IV. p. 267- Regular forms and cleavage unknown. Fracture not observable. Lustre imperfect metallic. Colour, blueish- black and greyish-black, passing into dark steel-grey. Streak brownish-black, shining. Opake. Brittle. Hardness — 5-0... 6-0. Sp. Gr. = 4- 1 45, a botryoidal variety. Compound Varieties. Heniform, botryoidal, fruticose : composition columnar, impalpable ; frac- ture flat conchoidal, even ; in a second composition it is curved lamellar, the faces of composition being smooth, rough, or granulated. Massive : compo- sition granular, impalpable, strongly connected, fracture flat conchoidal, even. OBSERVATIONS. 1. The tw& subspecies of Slack Iron-Ore, the Fibrous Black Iron-Ore, or Black Hematite, and the Compact Black Iron-Ore, differ from each other like the analogous varie- ties of rhombohedral and prismatic Iron-ore, or as Red and Brown Hematite differ from compact Red and Brown Iron-ore. 2. The mixture of the uncleavable Manganese-ore has ORDER VIII. PRISM ATOIDAL MANGANESE-ORE. 419 not been exactly ascertained. It is supposed to contain a considerable proportion of oxide of iron. It colours glass of borax violet-blue, like other ores of manganese. 3. It occurs, sometimes accompanied by prismatic Iron- ore, but generally along with other ores of manganese, in veins in ancient rocks, or also in porphyry. It has been found in several districts of Saxony, as at Spitzleite near Schneeberg,at Schimmelnear Johanngeorgenstadt,at Schle- gelsberg near Ehrenfriedersdorf, &c. It occurs, besides, in the Hollert mines in the district of Siegen, at Schmal- kalden in Hessia, at Ilefeld and other places in the Hartz. It has been found in various localities in Cornwall, Devon- shire, &c. in England. 3. PEISMATOIDAL MANGANESE-ORE. Prismatic Manganese-Ore (excepting the second subspe- cies). JAM. Syst. Vol. III. p. 251. Prismatdidai Man- ganese-Ore, or Grey Manganese*Ore. Man. p. 256. Grey Oxide of Manganese. PHILL. p. 243. Grauer Braunstein. WERN. Hoffm. H. B. IV. 1. S. 137. Grau-Braunstein. HAUSM. I. S. 258. Grau-?»Iangan- erz. LEONH. S. 371. Manganese oxyde' (excepting the appendix). HAUY. Traite', 2de Ed. p. 243. TabL comp. p. 110. Traite', 2de Ed. T. IV. p. 261. Fundamental form. Scalene four-sided pyramid. P = 1 30° 407, 120° 54', 80° 22'. Vol. I. Fig. 9. Ar. a : b : c = 1 : V3'37 ' V2'-*- Simple forms. P — oo (o) ; P (P) ; P -f- QD (M ) = 99°4(X; (ftr — l)^(y); (Pr + oo)* (,) = 76° 36<; (P + oo)* = 142° 42'; Pr (d) = 114°19/; Pr+oo; Pr+l=85°6'; Pr -f oo. Char, of Comb. Prismatic. Combinations. 1. P — oo. P + oo. Granam, Aberdeenshire. 2. Pr. P -f QD. Sim. Fig. 1. 420 PHYSIOGEAPHY. CLASS n. 3. Pr. P. P -f oo. Figs. 3. and 4. 4. P — GO. Pr. P. (Pr — I)5. P + OP. (Pr + QD)5. Fig. 27. The three last varie- ties from Ihlefeld in the Hartz. Cleavage, Pr + oo highly perfect, less distinct P -{- GO and P — oo. Fracture uneven. Sur- face of the vertical prisms streaked parallel to their edges of combination, often deeply furrow- ed ; Pr streaked parallel to the edges of combi- nation with P ; P — QD parallel to those with Pr ; Pr is often rough, the remaining faces ge- nerally smooth. Lustre metallic. Colour dark steel-grey, iron- black. Streak brownish-black. Opake. Brittle. Hardness = 2-5 . . . 3-0. Sp. Gr = 4-626, crystals from Ihlefeld. Compound Varieties. Twin-crystals: face of com- position parallel, axis of revolution perpendicular to a face of Pr = 122° 50'. Reniform, botryoidal, and other imitative shapes : surface generally rough and drusy ; composition columnar, of various sizes of individuals, often forming a second granular composition. Massive: composition granular or columnar, the individuals of the latter of various sizes, and often impalpable. In this case fracture becomes uneven, or earthy. OBSERVATIONS. 1. Grey Manganese-Ore has been divided into several sub- species, chiefly in regard to its mechanical composition. Radiated Grey Manganese-Ore comprises long acicular, or ORDER VIII. PRISM ATOIDAL MANGANESE-ORE. reed-like prisms, and such massive varieties as consist of columnar particles of composition, while the foliated one refers to short prisms and granular compositions. Compact Grey Manganese-Ore contains varieties, composed of im- palpable granular individuals ; and Earthy Grey Manganese- Ore, such as have lost their coherence, and appear in the state of an earthy powder. 2. The composition of some varieties, belonging to pris- matoidal Manganese-ore, has been found by KLApaoTHtobe Black Oxide of Manganese 90-50 89-00. Oxygen 225 10-25. Water 7'00 0-50. It is infusible before the blowpipe, and colours glass of borax violet-blue. It is insoluble in nitric acid. In heat- ed sulphuric acid it disengages oxygen, and chlorine is disengaged, if it is brought in contact with muriatic acid. Also before the blowpipe, or alone in a strong heat, it gives out oxygen. 3. The present species frequently accompanies prismatic and rhombohedral Iron-ore ; sometimes its earthy varieties constitute beds by themselves. It occurs often in veins, particularly in porphyry, along with prismatic Hal-baryte. 4. Several varieties of the species generally occur to- gether. They occur in abundance and great beauty at Ihlefeld in the Hartz, and at Oehrenstock near Ilmenau in Thuringia. But they are found likewise at Johanngeorgen- stadt and Eubenstock in Saxony, at Flatten in Bohemia, in several places in Hungary, in Moravia, Silesia, and France. They are met with also in different localities in England and Scotland. £5. The prismatoidal Manganese-ore is a useful mineral in the manufacture of glass, and painting in enamel. It is likewise essential in several chemical operations. If found along with iron-ores, it is said to be favourable to the quality of the iron extracted from the latter. 6. Black Wad, to which probably Brown Iron-Froth will be found to belong, deserves to be mentioned in the pre- sent place as a very remarkable mineral among those which PHYSIOGRAPHY. CLASSIC contain manganese. It occurs in reniform, botryoidal, fru- ticose, and arborescent shapes, in froth-like coatings on other minerals, &c., or also massive. Its composition is colum- nar, generally impalpable, and often curved lamellar, the fracture flat conchoidal, even, or earthy. Some varieties possess imperfect metallic lustre. The colour is brown, in various shades, the streak corresponding to the colour, only shining. It is opake, very sectile, soils and writes ; the hardness is about 0-5, specific gravity = 3706. It must be observed here, that although the varieties seem to be very light when lifted with the hand, yet they imbibe wa- ter with violence, as soon as they have been immersed into it, and they sink immediately ; from which it appears that those indications of the specific gravity which state it as being below I'O, must be erroneous. Black Wad mixed with lint-seed oil undergoes a spontaneous combustion. Ac- cording to KLAPROTH, a variety from the Hartz consists of Oxide of Manganese 68-00. Oxide of Iron 6'50. Water 17'50. Carbon 1-00. Baryta and Silica 9 '00. Brown Iron-froth is frequently found in various imitative shapes in geodes of prismatic Iron-ore. Black Wad pro- bably occurs under similar circumstances. Very fine va- rieties of the first are met with at Huttenberg, Friesach, Loben, and other places in Carinthia, also at Kamsdorf in Thuringia. The localities of Black Wad are particularly Devonshire and Cornwall, but also the Hartz and Pied- mont. This is probably also the colouring matter in the dendritic delineations upon steatite, limestone, and other substances. ORDER ix. NATIVE ARSENIC. 423 ORDER IX. METAL. GENUS I. ARSENIC. 1. NATIVE ARSENIC. Native Arsenic. JAM. Syst. Vol. III. p. 104. Man. p. 257. Native Arsenic. PHILL. p. 275. Gediegen Ar- senik. WERJT. Hoffm. H. B. IV. 1. S. 207. Gediegen Arsenik. HAUSM. I. S. 120. Gediegen- Arsenik. LEOXH . S. 164. Arsenic natif. HAUY. Trait^, T. IV. p. 220. TabL comp. p. 108. Trait**, 2de Ed. T. IV. p. 236. Regular forms and cleavage unknown. Lustre metallic. Colour tin- white, a little inclining to lead-grey, very soon tarnished dark-grey on being exposed to the air. Streak unchanged, ra- ther shining. Brittle. Hardness = 3-5. Sp. Gr. = 5.766, a Saxon variety. According to BERGMANN, that of the melted arsenic is = 8-308. Compound Varieties. Reticulated, reniform and stalactitic shapes : composition granular, small and often impalpable ; it is sometimes columnar, form- ing a second curved lamellar composition ; the indi- viduals being generally impalpable, and the faces of the second composition reniform or uneven. In co- lumnar particles of composition we may often observe cleavage in a direction perpendicular to the axis of the individuals. Massive, sometimes with impressions. OBSERVATIONS. 1. Native Arsenic is the pure metal as produced by na- ture. Two varieties yielded to JOHN, Arsenic 96-00 97'00. 424 PHYSIOGRAPHY. CLA83 II. Antimony 3-00 2-00. Oxide of Iron and Water 1-00 1-00. Upon ignited charcoal, or before the blowpipe, it emits a strong garlick smell, and copious white fumes, and at last disappears altogether. It is the volatilized metal, and not the white fumes of arsenious acid, which possess that odour. 2. It is most generally found in veins, seldom in beds, and is accompanied by hemi-prismatic Sulphur, rhombohe- dral Ruby-blende, and various species of the orders Metal, Pyrites, Glance, &c. Rarely it is met with along with hexahedral Gold and prismatic Tellurium-glance. 3. Native Arsenic is not uncommon in several of the mines of Annaberg, Schneeberg, Marienberg, and Frei- berg in Saxony ; it occurs at Joachimsthal in Bohemia, at Andreasberg in the Hartz, in the Black Forest, in Al- sace, at Allemont in Dauphiny, at Kongsberg in Norway, at Kapnik in Translyvania, and in beds at Orawitza in the Bannat of Temeswar. 4. It is variously employed in metallurgical processes, it enters into the composition of certain kinds of glass and of many colours, and has been introduced even among the pharmaceutical preparations. It is a violent poison. GENUS II. TELLURIUM. 1. NATIVE TELLURIUM. Hexahedral Tellurium. JAM. Syst. Vol. III. p. 118. Native Tellurium. Man. p. 258. Native Tellurium. PHILL. p. 326. Gediegen Silvan. WERN. Hoffm. H. B. IV. 1. S. 126. Gediegen-Tellur. HATJSM. I. S. 129. Gediegen -Tellur. LEONH. S. 180. Tellure natif ferri- fere et aurifere. HATJT. Traite', T. IV. p. 325. Tel- lure natif auro-ferrif ere. Tabl. comp. p. 119. Traite', 2de Ed. T. IV. p. 379. Form rhombohedral. Mr PHILLIPS quotes a com- bination similar to Fig. 112., the inclination at the base of the isosceles six-sided pyramid being ORDER ix. NATIVE TELLURIUM. 425 = 115° 12'. Cleavage in various directions, which have not been ascertained. Lustre metallic. Colour tin-white. Streak un changed. Rather brittle. Hardness = 2-0 ... 2-5. Sp. Gr. = 6-115, KLAPROTH. Compound Varieties. Massive : composition distinctly granular, individuals small ; sometimes a tendency to columnar composition. » OBSERVATIONS. 1. According to KLAPROTH, the native Tellurium con- sists of Tellurium 92-55. Iron 7'20. Gold 0-25. It melts easily upon charcoal before the blowpipe, burns with a greenish flame, and is volatilised. The odour of horse-raddish, which some varieties exhale, as has been ob- served by BEHZELIUS, is owing to selenium, and not to tellurium. 2. The native Tellurium occurs in sandstone probably in beds, or in veins which are of contemporaneous forma- tion with the rock. It is accompanied by rhombohedral Quartz and hexahedral Iron-pyrites, also by hexahedral Gold, particularly that variety in dust-like particles which is known among the collectors and mineral dealers in the Austrian states by the name of Spanish Snuff. 3. It has been found in pretty considerable quantities in the mine of Maria Loretto at Facebay near Zalathna in Transylvania. It is very rare at present. It was melted in order to extract the proportion of gold which it contains. 426 PHYSIOGRAPHY. CLASS II. GENUS III. ANTIMONY. 1. HHOMBOHEDRAL ANTIMONY. Dodecahedral Antimony. JAM. Syst. Vol. III. p. 110. Man. p. 250. Native Antimony. PHILL. p. 329. Ge- diegep Antimon oder Spiesglas. WERN. Hoff'm. H. B. IV. 1. S. 99. Gediegen-Spiessglanz. HAUSM. I. S. 125. Gediegen Antimon. LEONII. S. 150. Antimoine natif. HAUY. Traite, T. IV. p. 252. TabL comp. p. 112. Traitd, 2de Ed. T. IV. p. 279. Fundamental form. Rhombohedron. R = 117° 15'. Vol. I. Fig. 7. AP. a = V 1-273. Simple forms. R — oo ; R ; R + 2 = 69° 28' ; P -f- oo. Combinations not observed. Cleavage, R — oo highly perfect, and possessing a strong lustre ; R distinct and easily obtained, but shewing a less degree of lustre ; R -f- % dif- ficultly obtained and interrupted ; faint traces of P -f os. The result of all these cleavages is si- milar to Fig. 127, only the faces o and z are enlarged. Surface of R — oo triangularly streak- ed, R in a horizontal direction, and parallel also to its own edges. Fracture not observable. Lustre metallic. Colour tin-white. Streak un- changed. Rather brittle. Hardness = 3-0 ... 3-5. Sp. Gr. = 6-646, the Swedish variety. Compound Varieties. Reniform : surface reni- form or uneven ; composition of flat grains col- lected into curved lamellae. Massive : composi- tion granular of various sizes of individuals, easily ORDER IX. PRISMATIC ANTIMONY. separated ; faces of composition striated agreeably to the faces of cleavage. OBSERVATIONS. 1. According to KLAPROTH, the rhombohedral Antimony consists of Antimony 98-00. Silver 1-00. Iron 0'25. Before the blowpipe it melts quickly into a globule, and continues to burn, when heated to redness, even if the blast is suspended. It emits copious white fumes, which are deposited round the globule ; first yellowish-white oc- tahedrons, probably of antimonious acid, are formed, and then snow-white prismatic crystals of oxide of antimony, with which at last the whole globule is covered. Some of the varieties leave a globule of silver, when the contents of antimony have been entirely volatilized. It crystallises readily from fusion. 2. The rhombohedral Antimony is found in veins travers- ing ancient rocks, and is principally accompanied by other species that contain antimony. The Antimony Ochre, which also occurs with it, seems to be the product of its decom- position. 3. The present, species was first discovered at Sahlberg near Sahla in Sweden, and afterwards at Allemont in Dauphiny, where it occurs in curved lamellar compound varieties, which consist of granular ones, and at Andreas- berg in the Hartz. 2. PRISMATIC ANTIMONY. Octahedral Antimony. JAM. Syst. Vol. III. p. 113. Prismatic Antimony or Antimonial Silver. Man. p. 259. Antimonial Silver. PHILL. p. 286. Spiesglas- Silber. Arsenik-Silber. WERN. Hoffm. H. B. III. 2. S. 4G. 48. Silberspiessglanz. HAUSJI. I. S. 126. Anti- mon-Silber. LEONH. S. 204. Argent antirnoniaL PHYSIOGRAPHY. CLASS 11. HAUY. Trait e, T. III. p. 391. Tabl. comp. p. 74. Traite, 2de Ed. T. III. p. 258. Fundamental form. Scalene four-sided pyramid. Vol. I. Fig. 9. Simple forms. P — 00(0); P — 1 (z) ; P (y) ; P + oo (M) = 120° (nearly) ; £r ; Pr + 1 (P) ; £r -f QD (h). Char, of Comb. Prismatic. Combinations. 1. P — QD. P -f oo. ?r + oo. Andreasberg, Hartz. & P — oo. P— 1. P. Pr-fl. P+oo. £r-f oo. Fig. 28. Cleavage, P — QD and fr distinct, the former streaked parallel to the edges of combination with Pr ; imperfect in the direction of P + oo. Frac- ture uneven. Surface in general smooth. Lustre metallic. Colour silver-white, inclining to tin-white. Streak unchanged. Hardness rr 3-5. Sp. Gr. = 9*4406, HAUY ; = 9-820, KLAPJIOTH. Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpen- dicular to a face of P -f- oo. It is often repeated in parallel layers, or in layers parallel to both the faces of P + GO. The result is as in prismatic Lime- haloide, di^prismatic Lead-baryte, and other species, and similar therefore to Figs. 38. and 39. Mas- sive : composition granular, individuals of various sizes, and easily separated. Pseudomorphic six- sided prisms. ORDER IX. PRISMATIC ANTIMONY. 429 OBSERVATIONS. 1. The Arsenical Silver is considered by Professor HAUS- MANN as a more or less intimate mechanical mixture of native Arsenic or of prismatic Arsenical- pyrites with pris- matic Antimony ; and several mineralogists have regarded the Antimonial Silver and the Arsenical Silver as varieties of the same species. Very few of their properties have yet been ascertained ; among those which are known, the curved lamellar composition peculiar to Arsenical Silver, and its readiness to assume grey tarnished colours, the last of which, however, is, perhaps not without foundation, ascribed to native Arsenic, perhaps also specific gravity, may serve to distinguish it from Antimonial Silver. It appears, therefore, that an accurate examination of both substances is a thing yet very much wanted. Antimonial Silver occurs in crystals and massive varie- ties consisting of granular individuals ; Arsenical Silver is found in curved lamellar compositions, consisting of very thin crystalline coats. These are subject to tarnish. 2. According to KLAPROTH, the Antimonial Silver con- sists of 16-00 to 24-00 of antimony, and 84-00 to 76-00 of silver; the Arsenical Silver, according to the same au- thor, of Arsenic 35-00. Antimony 4-00. Silver 12-75. Iron 44-25. Before the blowpipe the pure varieties yield a globule of silver, while the antimony is driven off. 3. It is found in veins, accompanied by hexahedral Sil- ver, native Arsenic, hexahedral Lead-glance, and various other species. Antimonial Silver is found at Altwolfach in Fiirstenberg, and Andreasberg in the Hartz ; Arsenical Sil- ver, also in the Hartz, and Guadalcanal in Estremadura in Spain. 4. It is a rare mineral, and is highly valuable for extract- ing silver, wherever it is found in sufficient quantity. 430 PHYSIOGRAPHY. CLASS 11. GENUS IV. BISMUTH. 1. OCTAHEDRAL BISMUTH. Octahedral Bismuth. JAM. Syst. Vol. III. p. 107- Man. p. 260. Native Bismuth. PHILL. p. 272. Gediegen Wismutb. WE UN. Hoffm. H. B. IV. I. S. 65. Ge- diegen Wismuth. HAUSM. I. S. 123. Gediegen-Wis- muth. LEONH. S. 211. Bismuth natif. HAUY. Traite*, T. IV. p. 184. Tabl. comp. p. 105. Traite, 2de Ed. T. IV. p. 202. Fundamental form. Hexahedron. VoL I. Fig. 1. Simple forms. —, Bieber near Hanau ; -- -, Vol. I. Fig. 13. 14. ; D, Vol. I. Fig. 31. Char, of Comb. Semi-tessular, with inclined faces. Combinations. 1. — • — — • Fig. 158. Cleavage, octahedron, perfect, and easily obtained. Fracture not observable. Surface rough, gene- rally covered with a grey oxide. Lustre metallic. Colour silver-white, much inclin- ing to reel, subject to tarnish. Streak unchanged. Sectile, almost malleable. Hardness = 2-0 ... 2-5. Sp. Gr. = 9'737, a variety from Altenberg ; = 9-612, the melted metal. Compound Varieties. Imbedded feathery and arborescent shapes. Massive : composition granu- lar, individuals very distinct, though small. OBSERVATIONS. 1. This is the pure metal, as produced by nature. It is very fusible, and melts even at the flame of a candle. Be- fore the blowpipe it is volatilized, and leaves a yellow coat- OllDER IX. DODECAHEDRAL MERCURY. 431 ing upon the charcoal. It is soluble in nitric acid, but the solution yields a white precipitate, if farther diluted. It crystallises easily from fusion. 2. Octahedral Bismuth occurs chiefly in veins in gneiss and clay-slate, and is accompanied by ores of silver, cobalt, tin, &c. The Bismuth-ochre, which in a great measure depends upon the presence of that metal, is likewise often found along with it. 3. Its chief localities are several of the Saxon and Bo- hemian silver and cobalt mines at Schneeberg, Armaberg, Marienberg, Johanngeorgenstadt, Joachimsthal, &c. Large cleavable varieties have been found in the tin mine of Al- tenberg. It is found besides at Bieber in the principality of Hanau, in the Sophia mine at Wittichen in Fiirstenberg, at Loling in Carinthia, at Fahlun in Sweden, Modum in Norway, in France, &c. It occurs with ores of cobalt in Wheal Sparnon near Redruth, and with prismatic Bismuth- glance at Carrock in Cumberland. 4. It enters into the composition of several metallic al- loys used in the arts, and is employed in certain technical or metallurgic operations. GENUS V. MERCURY. 1. DODECAHEDRAL MERCORY. Dodecahedral Mercury, or Native Amalgam. JAM. Syst. Vol. III. p. 86. Man. p. 261. Native Amalgam. PHILL. p. 357. Natiirlich Amalgam. WEKN. Hoffm. H. B. III. 2. S. 21. Amalgam. HAUSM. I. S. 107- Amal- gam. LEONH. S. 207. Mercure argental. HAUY. Traite', T. III. p. 432. TabL comp. p. 77. Traite', 2de Ed. T. III. p. 307. Fundamental form. Hexahedron. Vol. I. Fig. I. Simple forms. H (z) ; O (r\ Vol. I. Fig. 2 ; D, Vol. I. Fig. 31. ; Aa (Qf Vol. I Fig. 32.; Ci (,9), Vol. I. Fig. 34.; Ti (Z), Vol. I. Fig. 35. Char, of Comb. Tessular. PHYSIOGRAPHY. CLASS II. Combinations. 1. O. D. 2. H. D. Ci. 3. H. O. D. As. Ci. Ti. All of them from Moschel- landsberg. Cleavage, very indistinct traces parallel to the dode- cahedron. Fracture conchoidal, uneven. Sur- face smooth and shining. Lustre metallic. Colour silver-white. Streak un- changed. Brittle ; it emits a grating noise when cut with a knife. Hardness = 3-0 ... 3-5. Sp. Gr. = 13-755, both observed in crystallised varieties. Compound Varieties. Massive: individuals scarce- ly discernible, fracture conchoidal, uneven. OBSERVATIONS. 1. Two kinds of native Amalgam have been distinguish, ed, in reference to the solid or fluid state in which it is found. The fluid varieties must be considered as solutions of the solid ones in fluid Mercury. 2. Dodecahedral Mercury consists of Silver 36-00. 27-50. Mercury 64-00. KLAPROTH. 72-50. CORDIER. Before the blowpipe the mercury is driven off, and we ob- tain a globule of pure silver. 3. The present species is always found in the repositories of peritomous Ruby-blende. It is accompanied by other ores of silver and mercury, and by hexahedral Iron-pyrites. 4. It occurs at Moschellandsberg in the Palatinate, and at Rosenau in Hungary ; it is said also to have been met with in France, Spain and Sweden. 2. FLUID MERCURY. Fluid Native Mercury. JAM. Syst. Vol. III. p. 83. Liquid Native Mercury. Man. p. 260. Native Quick- ORDER IX. HEXAHEDRAL SILVER. 433 silver. PHILL. p. 357. Gediegen Quecksilber. WERN*. Hoffm. H. B. III. 2. S. 18. Gediegen Quecksilber. HAUSM. I. S. 108. Gediegen-Quecksilber. LEOXH. S. 186. Mercure natif. HAUY. Traite, T. III. p. 423. Tabl. corap. p. 77- Traite', 2de Ed. T. III. p. 297. Amorphous. Liquid. Lustre metallic. Colour tin- white. Hardness == 0-0. Sp. Gr. = 13-581, HAUY. OBSERVATIONS. 1. Fluid Mercury is the* pure metal, as produced by nature. It is entirely volatile before the blowpipe, and easily soluble in nitric acid. 2. Lake the dodecahedral Mercury, it occurs in the re- positories of peritomous Ruby-blende, in the shape of small globules or drops. Sometimes it is found in narrow fissures of those rocks, which accompany that mineral. 3. The most important and well known localities of fluid Mercury are Idria in Carniola, and Almaden in Spain. In smaller quantities it is found at Wolfstein and Morsfeld in the Palatinate, also in some places in Carinthia, in Hun- gary, in Peru, and other countries. 4. The quantity of fluid Mercury found in nature is too small to allow of its being applied to any useful purposes. The metal obtained from the peritomous Ruby-blende, is employed for making thermometers and barometers, also in various chemical and pharmaceutical preparations, in the amalgamation of gold and silver ores, in the production of artificial cinnabar, in the processes of silvering mirrors, of gilding, and for many other purposes. GEKusVI. SILVER. 1. HEXAHEDRAL SILVER. Hexahedral Silver. JAM. Syst. Vol. III. p. 68. Man. p. 261. Native Silver. PHILL. p. 285. Gediegen VOL. II. 2 E 434 PHYSIOGRAPHY. CLASS n. Silber. WERN. Hoffm. H. B. III. 2. S. 38. Gediegen- Silber. HAUSM. I. S. 105. Gediegen-Silber. LEONH. S. 192. Argent natif. HAUY. Traite, T. III. p. 384. Tabl. comp. p. 73. Traite, 2de Ed. T. III. p. 249. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (r), Kongsberg, Norway ; O (n) Vol. I. Fig. 2., Mexico ; Cs (o) Vol. I. Fig. 34., Kongsberg. Char, of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4. 2. O. C«. Kongsberg. Cleavage, none. Fracture hackly. Surface, the octahedron striated in a triangular direction, parallel to its edges of combination with the hexa- hedron or the icositetrahedron. The remaining faces often rough, but even. Lustre metallic. Colour silver-white, more or less subject to tarnish. Streak shining. Ductile. Hardness = 2-5 ... 3-0. Sp. Gr. = 10-4743, HAUY. Compound Varieties. Twin-crystals, compound parallel to one of the faces of the octahedron. Denti- form, filiform and capillary shapes, also reticulated, arborescent and in plates. Often the individuals are still discernible, but frequently also their extent can be no longer ascertained. In the latter case the surface of the dentiform and filiform shapes is longitudinally streaked. Massive : composition scarcely observable, fracture hackly. Plates, form- ed in fissures, also superficial coatings. ORDER ix. IIEXAHEDRAL SILVER. 435 OBSERVATIONS. 1. Native Silver has been divided into common and awH. fcrcus native Silver. It is at present impossible to decide whether the latter ought to be united as a variety with the former, or whether it forms a species of its own ; as \ve are not yet sufficiently acquainted with all its physical properties, by which alone this question can be decided. Specific gravity and the yellowish colour form the distinc- tive marks between them ; but as these might be explain, ed by mere mechanical juxtaposition of the two metals, they are ffi)t alone sufficient for this purpose. 2. The common varieties present the pure silver, as produced by nature, occasionally alloyed with a small pro- portion of antimony, arsenic, iron, &c. A variety of the auriferous native silver yielded to KLAPROTH, and another to FORDYCE, the following ingredients : Silver 36-00 72-00. Gold 54-00 20-00. The hexahedral Silver is soluble in cold nitric acid, but in sulphuric acid only with the assistance of heat. It crys- tallises from fusion*. 3. Hexahedral Silver occurs principally in veins, tra- versing gneiss, clay-slate, and other primitive and transi- tion rocks. It is accompanied by numerous species of the orders Kerate, Metal, Pyrites, Glance, and Blende, also by rhombohedral Quartz, rhombohedral and macrotypous Lime-haloide, &c. The auriferous native silver, though it is found in the same repositories, is far more scarce. The formation of Black Silver, a black, friable substance, which is very rich in silver, seems to depend chiefly upon the pre- sence of native Silver, or also of hexahedral Silver-glance. * A globule of silver melted before the blowpipe, if not too large, forms while crystallising a single individual, in which the faces of the octahedron, the hexahedron, and the dodecahedron may be most distinctly traced, and admit of measurement by the reflective goniometer, but particularly those of the octahe- dron. The surface of the globule appears reticulated. H. 436 PHYSIOGRAPHY. CLASS IT. 4. There are but few countries in which hexahedral Sil- ver is found in any considerable quantity. Among these are the mining districts of Saxony and Bohemia, also Nor- way and Siberia, but particularly Mexico and Peru. It occurs more sparingly in the Hartz, in Hungary, in Swa- bia and Franconia, and other countries. The Saxon va- rieties are chiefly known from Freiberg, Schneeberg, Jo- hanngeorgenstadt, &c. ; the Bohemian varieties from Joa- chimsthal, Przibram, Ratiborzitz, &c. Large and well de- fined crystals were formerly found at Kongsberg in Nor- way. It is met with at Andreasberg in the Hartz, at Alt- wolfach in Swabia, in the Dauphiny, in France, at Schem- nitz in Hungary, &c. ; it is found likewise in Wheal Mexi- co, Wheal Duchy, and several other mines of Cornwall. The localities of auriferous native Silver are Kongsberg in Norway, and Schlangenberg in Siberia. 5. The employment of silver in coinage, in the manu- facture of plate, and of various articles of luxury, is well known. Other metals are frequently covered with a coat of it ; it is useful in the construction of several parts of the chemical and philosophical apparatus, for which, however, it is required to be perfectly pure. It is used also in phar- macy. GENUS VII. GOLD. 1. HEXAHEDRAL GOLD. Hexahedral Gold. JAM. Syst. Vol. III. p. 55. Man. p. 262. Native Gold. PHILL. p. 322. Gediegen Gold. WERN. HofFm. H. B. III. 1. S. 10. Gediegen-Gold. Electrum. HAUSM.LS.100.102. Gediegen-Gold. LEONH. S.177. Or natif. HAUY. Traite', T. III. p. 374. TabL comp. p. 73. Traite, T. III. p. 235. Fundamental form. Hexahedron. Vol. I. Fig. 1 . Simple forms. H(r), Transylvania; O(w). Vol.1. Fig. 2. Siberia; D (s) Vol. I. Fig. 31., Catharinen- ORDER ix. HEXAHEDRAL GOLD. 437 burg, Siberia ; As, Vol. I. Fig. 32., Siberia ; Cfi (o) Vol. I. Fig. 34., Transylvania. Char, .of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4., Matto Grosso, Brazil. 2. H. D. Fig. 151. 3. H. C*. Fig. 153. 4. H. O. C*. The three last from Transylvania. Cleavage, none. Fracture hackly. Surface ; the hexahedron often hollow ; the octahedrons either rough or smooth, in combinations generally the latter ; the icositetrahedrons streaked parallel to the edges of combination with the hexahedron and the octahedron. These differences in most cases are not distinctly marked. Lustre metallic. Colour, various shades of gold- yellow. Streak shining. Ductile. Hardness — 2-5... 3-0. Sp. Gr. = 14-857, a rolled mass of a high gold-yellow colour; = 19-2527, melted, HAUY. Compound Varieties. Twin-crystals: face of composition parallel, axis of revolution perpendicu- lar to a face of the octahedron ; pretty frequent, particularly in the icositetrahedrons, as represented in Fig. 157. If this variety be compressed in the direction of the axis of revolution, Fig. 178 is formed, having the appearance of an isosceles six- sided pyramid combined with a three-sided one, similar to the crystals, which are described in the Catalogue of the Collection of Mr VON DER NULL, Part III. p. 42., but without mentioning the regu- 438 PHYSIOGRAPHY. CLASS n. lar composition upon which they depend. Filiform, capillary, reticulated, and arborescent shapes, also leaves or membranes. Sometimes the individuals are still discernible, but frequently also they can be no longer recognised. Surface drusy, striated, or smooth. Massive : composition not observable, fracture hackly. Plates, superficial coatings, rolled masses. OBSERVATIONS. 1. Although the division which has been introduced in the present species into gold-yellow, 'brass-yellow, and greyish- yellow Native Gold, seems with some slight modifications to agree with the geological relations of its varieties ; it is yet as little deserving of acceptance as any other division within a natural-historical species. The gold-yellow va- rieties comprise the specimens of the highest gold-yellow colours, though there are some among them which have a rather pale colour ; they include most of the crystals, and of the imitative shapes, in fact the greater part of the species itself. The brass-yellow native Gold is confined to some of the regular and imitative shapes, of a pale co- lour, which is generally called brass-yellow, and, as it is said, of a less specific gravity than the preceding one ; but this does not seem to have ever been ascertained by direct experiment. The greyish-yellow native Gold occurs only in those small fiat grains which are mixed with the native Platina, and possess a yellow colour a little inclining to grey ; they are said to have the greatest specific gravity of them all. The real foundation of this distribution seems to be the opinion that the first are the purest, the second mixed with a little silver, and the third with platina. It is not known whether the latter admixture really takes place, but it is certain that several varieties of gold-yellow native Gold contain an admixture of silver. Some mi- neralogists unite the auriferous native Silver not improper- ly with the present species. OHDER IX. HEXAHEDRAL GOLD. 439 2. A variety of the brass-yellow native Gold has yielded to LAMPADIUS, Gold 96-60. Silver 2-00. Iron 1*10. Hexahedral Gold melts pretty easily, and is soluble only in chlorine or nitro-muriatic acid. Gold may be obtained crystallised from fusion. A solution of muriate of gold in sulphuric ether yields hexahedral crystals on evaporation. Brilliant crystals of the compound form of the hexahedron, octahedron, and dodecahedron, have been accidentally form- ed by exposing for several years an amalgam of gold wrapt up in cotton. 3. The hexahedral Gold is so minutely disseminated in several rocks, that its presence can be discovered only after pounding and washing. It occurs frequently in beds, in small nodules, imbedded in rhombohedral Quartz ; it is more rarely met with in imbedded crystals. It occurs in veins traversing various kinds of rocks, sometimes very short and narrow, presenting a great variety of crystals and imitative shapes. In beds it is generally accompanied by rhombohedral Quartz and hexahedral Iron-pyrites, some- times also by prismatoidal Antimony-glance and pyrami- dal Scheelium-baryte. In veins it occurs along with near- ly the same minerals, but likewise with many others, of the orders Glance, Pyrites, Blende, Baryte, Haloide, Metal, &c. Hexahedral Gold is often found in the sand of rivers, in valleys and plains into which it has been carried from its original repositories, in the shape of larger or smaller, ge- nerally flat pebbles, often mixed with rhombohedral Quartz. From the generally high gold-yellow colour of these varie- ties, it seems probable that they are derived from beds or mountain masses, and not from veins. The greyish-yellow native Gold occurs in a similar manner along with native Platina. In this kind of repositories it is accompanied by octahedral Iron-ore, peritomous Titanium-ore, (for instance, the Nigrine from Ohlapian), and several species of gem, among which pyramidal Zircon is not rare* 440 PHYSIOGRAPHY. CLASS n. 4. The greatest quantity of hexahedral Gold is found in alluvial soil in Brazil, Mexico, and Peru, sometimes in pebbles of considerable size. The imbedded crystals from Matto Grosso in Brazil indicate a formation in beds, or rocks. Also in Transylvania a considerable quantity of gold is obtained from Streamworks, as at Ohlapian near Hermannstadt. At Wicklow in Ireland, near Leadhills, and in Perthshire in Scotland*, in several districts of Ger- many and in other countries, gold is found in the sand of rivers, or in alluvial deposits from them. It has been ob- served that the Rhine, the Danube, and others rivers are auriferous only in plains, from whence it should seem, that the gold is engaged in the diluvium. The mountain of Vo- rospatak near Abrudbanya in Transylvania, is a remarkable instance of a rock impregnated throughout with a small portion of gold, which occurs crystallised and in various imitative shapes in the numerous short and narrow veins which traverse it in all directions. This mountain has been worked to a considerable extent since the time of the Ro- mans ; it consists of a kind of greywacke and porphyry. Gold occurs in beds at Posing, Botza, Magurka, and other places in Hungary, also in the Bannat with dodecahedral Garnet, but here more rarely. In the same kind of repo- sitories it is found at Schellgaden in Lungau, also in the valleys of Gastein, Rauris, Fusch, &c. in Salzburg, and in many other places along the chain of the Alps ; in the Schlan- genberg in Siberia, &c. It is met with in veins at Crem- nitz and Schemnitz in Lower Hungary, and in many dis- tricts of Transylvania, as at Offenbanya, where it is ac- companied by prismatic Antimony-glance, at Zalathna, where it is accompanied by native Tellurium, and in seve- ral mines between Nagyag and Boitza. At Nagyag it oc- curs along with the prismatic Tellurium-glance. * The variety from Leadhills is of a high yellow colour, that from Turrich in Glen Coich in Perthshire is very pale. A specimen of the latter in Mr ALLAN'S collection weighs upwards of seven guineas. H. OADER IX. NATIVE PLATINA. 441 5. The use of hexahedral Gold is in many respects analo- gous to that of hexahedral Silver, and perhaps even more extensive. GENUS VIII. PLATINA. 1. NATIVE PLATINA. Native Platina, JAM. Syst. Vol. III. p. 49. Man. p. 264. Native Platina. PHILL. p. 324. Gediegen Platin. WERN. Hoffm. H. B. III. 2. S. 7- Polyxen. HAUSM. I.S.97. Gediegen-Platin. LEONH. S. 1.74. Platinenatif ferrifere. HAUY. Traite', T. III. p. 368. TabLcomp. p. 72. Traite', 2de Ed. T. III. p. 226. Irregular forms, grains. Surface uneven, some- times worn off by attrition (pebbles). Cleavage none. Fracture hackly. Lustre metallic. Colour perfect steel-grey. Streak unchanged, shining. Ductile. Hardness =4-0 ... 4-5. Sp. Gr. = 17-332, rolled masses. OBSERVATIONS. 1. Native Platina generally contains a little iron. It is accompanied besides by indium, osmium, rhodium, palla- dium, and also by copper, chrome, and titanium. It is very refractory, and soluble only in nitro-muriatic acid. 2. The original repositories of native Platina are not known, it having hitherto been found only in pebbles and grains, generally small, but sometimes upwards of a pound and a half in weight. It is accompanied by pyra- midal Zircon and some other gems, also by octahedral Iron-ore, hexahedral Gold, and native Indium and Pal- ladium. 3. Native Platina is principally found in South America, in the provinces of Choco and Barbacoas ; also at Matto Grosso in Brazil. It has also been found in St Domingo. 412 PHYSIOGRAPHY. CLASS II. 4. The refractory property of this metal, and the cir- cumstance that it is not acted upon by the greater part of the chemical reagents, render it extremely valuable in the construction of philosophical and chemical apparatus. It is used also for covering other metals, for painting on por- celain, and, like gold or silver, for various other purposes. GENUS IX. IRON. 1. OCTAHEDRAL IRON. Octahedral Iron (excepting the first subsp.). JAM. Syst. Vol. III. p. 97. Man. p. 264. Native Iron. PHILL. p. 213. Gediegen Eisen. WEIIN. Hoffm. H. B. III. 2. S. 187. Meteoreisen. HAUSM. I. S. 114. Gediegen- Eisen. LEONH. S. 319. Fer natif. HAUY. Tabl. comp. p. 93. Traite, 2de Ed. T. III. p. 531. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple form. O, Vol. I. Fig. 2. Irregular forms, grains. Cleavage none. Fracture hackly. Surface rough, the grains rough and uneven. Lustre metallic. Colour pale steel-grey. Streak unchanged, shining. Strong action upon the magnet. Ductile. Hardness = 4-5. Sp. Gr. = 7-768, the meteoric variety from Elbogen. Compound Varieties. Small crystals arranged in rows. The composition in large masses becomes visible, if an artificial surface is produced by cut- ting and polishing, and this surface exposed either to the action of nitric acid, or allowed to tarnish by heat. The surface of the masses is commonly oxid- ised, and sometimes marked with impressions of prismatic Chrysolite. ORDER IX. OCTAHEDRAL 1110X. 443 OBSERVATIONS. 1. The masses of octahedral Iron, from Agrani, Siberia, and Mexico, analysed by KLAPHOTH, have yielded Iron 96-50 98-50 96'75. Nickel 3-50 1-50 3-25. It contains sometimes a larger proportion of nickel. Pro- fessor STROMEYER has found some cobalt in the variety from the Cape. The octahedral Iron is infusible before the blowpipe, soluble in acids, and resembling pure iron in most of its properties. 2. The octahedral Iron is found in detached masses of various sizes on the surface of the earth. It enters into the composition of several kinds of meteoric stones, along with Iron-pyrites, with which it has been originally pro- duced. Those large masses, which are found without earthy admixtures, must yet be supposed to have had the same origin. It is not decided whether the terrestrial native Iron is a natural production. It agrees pretty nearly in regard to several of its properties with the meteoric Iron. The variety from Kamsdorf in Saxony, besides 92-50 of iron, yielded to KLAPROTH 6-0 of lead, and 1-5 copper. The native steel from La Bouiche in France, engaged in an iron-slag, appears to be of a secondary formation, owing to the combustion of a coal seam. 3. Among the most remarkable of the masses found on the surface of the earth, we notice that discovered by PAL- LAS in Siberia, which contains crystals and grains of pris- matic Chrysolite ; that discovered by Don RUBIN DE CE- LIS in the district of Chaco-Gualamba in South America, one of the largest known ; that of Elbogen in Bohemia, and that of Agram in Croatia, which, according to credible Avitnesses, was seen falling from the sky in two pieces. Many masses are scattered over the continent of North America, as in Louisiana, and still farther north, in the countries inhabited by the Esquimaux; several masses have also been found in Africa, as on the Senegal river, and near the Cape of Good Hope. The greater part of the 444 PHYSIOGRAPHY. CLACS n. mass from Elbogen, and the larger specimen of those which fell at Agram, are preserved in the imperial cabinet at Vienna, which, besides, contains an extensive and interest- ing collection of meteoric stones. Masses of this kind, containing octahedral Iron, are those from Erxleben, be- tween Halberstadt and Magdeburg, from Ensisheim, from TAigle, and others. 4. Octahedral Iron has been worked as an object of cu- riosity into knives, swords, and other instruments. It forms the substance of the rough shaped knives of some of the Esquimaux tribes in North America. GENUS X. COPPER. 1. OCTAHEDRAL COPPER. Octahedral Copper. JAM. Syst. Vol. III. p. 89. Man. p. 265. Native Copper. PHILL. p. 296. Gediegen Kup- fer. WERN. Hoffm. H. B. III. 2. S. 84. Gediegen- Kupfer. HAUSM. I. S. 111. Gediegen-Kupfer. LEONH. S. 251. Cuivre natif. HAUY. Traite', T. III. p. 518. Tabl. comp. p. 85. Traite', 2de Ed. T. III. p. 423. Fundamental form. Hexahedron. Vol. I, Fig. 1 . Simple forms. H (r) ; 6 (n), Vol. I. Fig. 2 ; D (s), Vol. I. Fig. 31., Lizard, Cornwall ; Aa, Vol. I. Fig. 32., Nalsoe. Char, of Comb. Tessular. Combinations. 1. H. O. Vol. I. Fig. 3. and 4., Cornwall. 2. H. D. Fig. 151. 3. H. O. D. 4. H. O. D. A 2. The three last from Siberia. Cleavage none. Fracture hackly. Surface gene- rally not very smooth, but nearly of the same quality in all the forms, only the dodecahedron is sometimes streaked parallel to the edges of combination with the hexahedron. It is subject to tarnish. ORDER IX. OCTAHEDEAL COPPER. 445 Lustre metallic. Colour copper-red. Streak un- changed, shining. Ductile. Hardness = 2-5 ... 3-0. Sp. Gr. = 8-5844, HAUY. Compound Varieties. Twin-crystals very fre- quent, composed parallel to a face of the octahe- dron. If the form of the individuals is the icosite- trahedron A 2, and the compound crystal flattened in the direction of the axis of revolution, isosceles six-sided pyramids are formed, which at first sight appear not to belong to the tessular system. Small crystals aggregated in rows ; arborescent and fili- form shapes. Massive: composition not recognis- able. Plates, often consisting of distinct crystals. Superficial. OBSERVATIONS. 1. The octahedral Copper is the pure metal as produced by nature. Before the blowpipe it melts pretty easily, but is covered on cooling with an oxidised coat. It is easily soluble in nitric acid, and yields under the influence of light and air, a blue solution in ammonia. It crystallises from fusion ; crystals, dentiform and capillary shapes, are often produced in the vesicular cavities of copper-slags. 2. It is found in beds and veins, and is associated with various other ores of copper, sometimes with ores of iron, &c. 3. Among the metals, hexahedral Copper is one of those which are not uncommonly found in the native state ; and even in our times examples have occurred of large masses that have been met with in several countries. In beds it occurs at Herrengrund, Schmolnitz, and Gollnitz ; also at Moldawa, Saska, and Orawitza, in the Bannat of Temes- war ; probably in the same manner in Siberia, from whence the largest and most distinct crystals of the general shape of the hexahedron have been brought, for the greater part 44-6 PHYSIOGRAPHY. CLASS II. engaged in granular limestone. It occurs likewise in beds in bituminous marl-slate at Camsdorf in Thuringia, and in the county of Mansfeld, and in sandstone at Chessy near Lyons. In veins it is met with in considerable quantities in many of the mines near Iledruth in Cornwall, in small quantities in several of the Shetland isles, and formerly in the neighbourhood of Freiberg. Octahedral Copper is found along with axotomous Triphane-spar in amygdaloid at Ober- stein in the Palatinate and in Transylvania, and in a simi- lar rock with rhombohedral Kouphone-spar in Nalsoe, one of the Faroe islands ; in the last place in beautiful icositetra- hedrons of the form Vol. I. Fig. 32. It occurs besides in many localities of Germany, Spain, Norway, America, China, &c. It is sometimes formed in the fissures of those rocks which surround the repositories of various ores of Copper, as in the vicinity of Moldawa in the Bannat. What has been called copper of cementation^ is the metal precipitated from its solution in sulphuric acid, by metallic iron. It is pro- duced at Herrengrund and Schmolnitz in Hungary, and in Cornwall. 4. Copper allows of a very extensive and well known employment in the arts and manufactures, as in roofing houses, coppering ships, coining, and in the fabrication of various utensils. The discovery of Sir HUMPHRY DAVY, that copper may be guarded against the influence of sea- water, by negatively electrifying its surface, will no doubt enlarge its application in the coppering of vessels. ORDER X. PYRITES. GENUS I. NICKEL-PYRITES. 1, PRISMATIC NICKEL-PYRITES. Prismatic Nickel-Pyrites. JAM. Syst. Vol. III. p. 266. Man. p. 266. Copper Nickel. Arsenical Nickel. PHILL. p. 283. Kupfernickel. WERN. Hoffm. H. B. IV. 1. S. 164. Kupfernickel. HAUSM. I. S. 118. Arsenik- Nickel. LEONH. S. 292. Nickel arsenical. HAUY. ORDER X. PRISMATIC NICKEL-PYRITES. 447 Traite, T. III. p. 513. Tabl. comp. p. 84. Traite, 2de Ed. T. III. p. 417- Fundamental form. Scalene four-sided pyramid of unknown dimensions. Vol. 1. Fig. 9. Simple forms and the character of combination not satisfactorily ascertained. The latter seems to be nearly allied to those of prismatic Iron-pyrites, of diprismatic Lead-bary te, &c. particularly in re- gard to the regular compositions in which their individuals occur. Cleavage unknown, imperfect. Fracture small conchoidal, uneven. Surface smooth. Lustre metallic. Colour copper-red. Streak pale brownish-black. Brittle. Hardness = 5-0 ... 5-5. Sp. Gr. =7-655. Compound Varieties. Reniform : composition columnar, generally impalpable. Massive : com- position granular, the individuals being small, and strongly connected. Fracture uneven. OBSERVATIONS. 1. According to two analyses, one by STROMEYER, and another by PFAFF, the prismatic Nickel-pyrites consists of Nickel 44-206 48-90. with a little Cobalt. Arsenic 54-726 46-42. Iron 0-337 0-34. Lead 0-320 0-56. Sulphur 0-401 0-80. It is represented by the chemical formula Ni As, which corresponds to 44-01 of nickel and 55-99 of arsenic. Be- fore the blowpipe it melts upon charcoal, and emits an arsenical smell. The remaining metallic bead is white 418 PHYSIOGRAPHY. CLASS II. and brittle. In nitric acid it soon becomes covered with a green coating. It is soluble in nitro-muriatic acid. 2. The prismatic Nick el -pyrites chiefly occurs in veins, in various classes of rocks, and is more rarely met with in beds. It is almost always accompanied by octahedral Co- balt-pyrites, sometimes also by ores of silver and lead. The apple-green friable substance called Arseniatc of Nickel or Nickel Ochre (Nickel arseniate. HAUY), found investing the prismatic Nickel-pyrites, is produced by the decom- position of this mineral, and consists of 37*35 oxide of nickel and a little cobalt, of 36-97 arsenic acid, and 24-32 of water, together with a little oxide of iron and sulphuric acid, according to ST no MEYER. 3. The present species is found in veins at Schneeberg, Annaberg, Marienberg, Freiberg, Gersdorf, and other places in Saxony ; at Joachimsthal in Bohemia ; at Saal- feld in Thuringia ; at Riegelsdorf in Hessia ; in the Hartz and the Black Forest ; also at Allemont in Dauphiny, and in several of the mines in Cornwall. In beds it occurs at Schladming in Upper Stiria, and in the neighbourhood of Orawitza in the Bannat. Mr DOEBEREINER has observed that the metallic alloy, consisting chiefly of arsenic and nickel, which is obtained from the process of fabricating smalt, often crystallises in four-sided tabular crystals, and is in every respect similar to prismatic Nickel-pyrites. GENUS II. ARSENICAL-PYRITES. 1. AXOTOMOUS ARSENICAL-PYRITES. Prismatic Arsenical-Pyrites. JAM. Syst. S^ol. III. p. 272, Axotomous Arsenic-Pyrites. Man. p. 268. Fundamental form. Scalene four-sided pyramid. P = 117° 28', 90°5r, 121° 58'. Vol. I. Fig. 9. AP. a : b : c = 1 : V0'8?4? : V0'4806- Simple forms. Pr (o) = 51° 20' ; P + oo (d) ORDER x. PRISMATIC ARSENICAL PYRITES. 449 Char, of Comb. Prismatic. Combination. Pr. P-f oo. Fig. 1. Schladming, Stiria. Cleavage, P — oo, perfect; less distinct j?r =86° 1(X; traces of P + oo. Fracture uneven. Surface faintly streaked parallel to the common edges of combination, frequently smooth. Lustre metallic. Colour between silver-white and steel-grey. Streak greyish-black. Brittle. Hardness = 5-0 ... 5 5. Sp. Gr. = 7*228, the massive variety from Reichenstein. Compound Varieties. Massive: composition gra- nular, individuals small, often nearly impalpable, and strongly connected, fracture uneven ; compo- sition columnar, rather thick and irregular, and di- vergent. Faces of composition irregularly streaked. OBSERVATIONS. 1. The axotomous Arsenical-pyrites contains arsenic and iron, the proportions of which have not been ascertained. 2. As far as our present information goes, the axotomous Arsenical-pyrites has been found only in beds, either along with brachytypous Parachrose-baryte and prismatic Iron- ore, or imbedded in serpentine. With the first it occurs in the valley of Loling near Hiittenberg in Carinthia, in serpentine at Reichenstein in Silesia. It has likewise been met with in beds in primitive mountains, with Nickel-py- rites and Cobalt-pyrites at Schladming in Stiria, 2. PRISMATIC ARSENICAL-PYRITES. Di-prismatic Arsenical Pyrites. JAM. Syst. VoL III. p. 272. Prismatic Arsenic-Pyrites. Man. p. 268. Arsenical Iron. Mispickel. PHILL. p. 215. Arsenikkies. WERN. Hoffm. H. B. IV. 1. S. 211. Arsenikkies. HAUSM. I. S. 153. Arsenikkies. LEONH. S. 332. Fer arse- 450 PHYSIOGRAPHY. CLASS n. nical. HAUY. Trait^, T. IV. p. 56. Tabl. comp. p. 95. Traite, 2de £d. T. IV. p. 28. Fundamental form. Scalene four-sided pyramid. P = 131° 51', 105° 56', 93° 20'. Vol. I. Fig. 9. AP. a : b : c = 1 : V2'83 : V1'30- Simple forms. P — x ; P + oo (M) = III0 53'; p r _ 1 (r) = 145° 26'; Pr (s) = 118° 32'; ?r + 1 = 80° 8'; Pr + OD; Pr + 1 = 59°22'. Char, of Comb. Prismatic. Combinations. 1. Pr — 1. P -f oo. Fig. 2. Freiberg, Saxony. 2. Pr. Pr +1. P + OD. Wheal Maudlin, Cornwall. 3. ?r — 1. Pr+1. P-HOO. Ehrenfriedersdorf, Saxony. 4. P — oo. Pr + 1. Pr + 1. P + oo. Wheal Maudlin. Cleavage, P -f QD pretty perfect, traces of P — oo. Fracture uneven. Surface, Pr — 1 deeply streaked parallel to its own edges ; Pr sometimes rough, or striated in the direction of its edges of combination with JPr — 1 ; the remaining faces are smooth. Lustre metallic. Colour silver. white, inclining and passing into steel-grey. Streak dark greyish- black. Brittle. Hardness = 5-5 . . . 6-0. Sp. Gr. = 6-127, of a crystallised variety. Compound Varieties. Twin- crystal : 1. Face of composition parallel, axis of revolution perpendicu- lar, to a face of Pr -f 1, the individuals being con- ORDER X. PllISMATIC ARSENICAL-PYRITES. 451 tinued beyond the face of composition. &. Face of composition parallel, axis of revolution perpen- dicular to a face of P -f oo ; the composition often takes place parallel to both faces, or is repeated in parallel layers. Massive: composition columnar, individuals of various sizes, generally straight and divergent or irregular. The faces of composition are irregularly streaked. Individuals joined m a granular composition are often very small, or even impalpable, and strongly connected ; their fracture is uneven. OBSERVATIONS. 1. Two subspecies, the common Arsenical pyrites and the argentiferous Arsenical pyrites, have been distinguished among the varieties of the present species, which, how- ever, differ chiefly in a small proportion of silver which the latter contains, and which has probably been the only rea- son of this distinction having been introduced. The latter contains only a few varieties in small imbedded acicular crystals and massive nodules, while all the rest rank under the head of common Arsenical pyrites. 2. According to STROMEYER, the prismatic Arsenical- pyrites consists of Iron 36-04. Arsenic 42-88. Sulphur 21-08. It is considered by BERZELIUS to be Fe As2 -f Fe S4, which corresponds to 33-5 of iron, 46-5 of arsenic, and 20-0 of sulphur. Before the blowpipe upon charcoal it emits copious arsenical fumes, and melts into a globule, which is nearly pure sulphuret of iron. It is soluble in nitric acid, with the exception of a whitish residue. 3. Prismatic Arsenical-pyrites is a pretty common mine- ral both in beds and veins. It is accompanied by ores of 45£ PHYSIOGRAPHY. , CLASS if. silver, lead, and tin, by several species of the order Pyri- tes, very frequently by rhombohedral Quartz, and it is scarcely ever found without dodecahedral Garnet-blende. 4. Prismatic Arsenical-pyrites is plentiful in several of the mining districts of Saxony ; it is found in beds at Breitenbrunn and Raschau, in veins at Freiberg, Munzig, &c., also in the tin-veins and beds of Altenberg, Geyer, Ehrenfriedersdorf, and other places. In Bohemia it is found in the silver mines of Joachimsthal and the tin mines of Schlaggenwald. Reichenstein and Kupferberg in Sile- sia, which are quoted as localities, are rather doubtful, no attention having hitherto been paid to the difference between the two species of prismatic and axotomous Arse- nical pyrites. It occurs at Andreasberg in the Hartz, at Tunaberg in Sweden, at Wheal Maudlin and other mines in Cornwall, and in many other countries. The argentiferous variety is principally found at Braunsdorf near Freiberg, in quartzy veins in mica-slate. A variety in small acicular crystals, much resembling the preced- ing one, but containing no silver, is found in sandstone, in a place called Braza, near Zalathna in Transylvania. 5. The accidental admixture of silver renders some va- rieties of the present species useful as ores of that metal. The common Arsenical pyrites is employed in the manu- facture of white arsenic and of realgar. Sometimes it con- tains a small proportion of gold. GENUS III. COBALT- PYRITES. 1. OCTAHEDRAL COBALT-PYRITES. Octahedral Cobalt-Pyrites. JAM. Syst. Vol. III. p. 282. Octahedral Cobalt-Pyrites or Tin-White Cobalt. Man. p. 269. Bright White Cobalt. PHILL. p. 270. Weisser Speiskobold. WERN. Hoffm. H. B. IV. 1. S. 173. Speiskobalt. HAUSM. I. S. 155. Speiskobalt. LEONH. S. 299. Cobalt arsenical. HAU Y. Traite, T. IV. p. 200. Tabl. comp. p. 106. (excepting C. a. gris-nomltre). ^, 2de Ed. T. IV. p. 2 1 9. (with .the same exceptions). OBDERX. OCTAHEDBAL COBALT-PYKITES. 453 Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (r), Schladming, Stiria ; O (n), Vol. I. Fig. 2., Schneeberg, Saxony; D (s). Vol. I. Fig. 31. ; Ci (o), Vol. I. Fig. 34. Char of Comb. Tessular. Combinations. l.H.O.,Vol. I.Fig.3and4.Dobschau, Hungary. 2. H. D. Fig. 151. 3. H. O. D. 4. H . O. D. C i . The three last from Schneeberg. Cleavage, traces in the direction of the octahedron, the hexahedron and the dodecahedron, the first sometimes a little more distinct. Fracture un- even. Surface generally pretty smooth, the faces of the hexahedron often curved. Subject to tarnish. Lustre metallic. Colour tin-white, inclining to steel-grey. . Streak greyish-black. Brittle. Hardness = 5-5. Sp. Gr. = 6-466, a cleavable variety. Compound Varieties. Reticulated and some other imitative shapes ; the individuals of them being often discernible. Massive : composition granular, individuals of various sizes, but general- ly small and strongly connected. Fracture uneven OBSERVATIONS. 1. According to STROMEYER, the octahedral Cobalt-py- rites consists of Cobalt 20-31. Arsenic 74-21. Iron 3-42. Copper 0-15. Sulphur 0-88. 454 PHYSIOGRAPHY. CLASS II. Its chemical formula is Co As3 or Go As2 + Co As4, cor- responding to 22-30 of cobalt and 77*70 of arsenic. Before the blowpipe it emits copious fumes and odour of arsenic. It melts into a white brittle metallic globule. To borax and other fluxes it imparts a blue colour. It affords a pink solution with nitric acid, leaving a white residue, which is itself dissolved on farther digestion. 2. Octahedral Cobalt-pyrites is principally met with in veins, traversing rocks of various ages, more rarely in beds. It is accompanied by ores of silver, or by ores of copper, and along with the first sometimes by octahedral Bismuth and prismatic Cobalt-mica. In beds it is associated with Arsenical-pyrites and Lime-haloides, and rarely it is found without the prismatic Nickel-pyrites. 3. In veins traversing primitive rocks it occurs at Schnee- berg and Annaberg in Saxony ; also at Freiberg and Ma- rienberg ; likewise at Joachimsthal in Bohemia, and in veins in killas at Wheal Sparnon in Cornwall. The veins of the counties of Sayn and Siegen, which contain it, are included in greywacke, and those of Thuringia and Mansfeld, and of Biechelsdorf in Hessia, in cupriferous shale. It occurs in beds at Schladming in Stiria, at Orawitza in the Bannat, and at Dobschau in Hungary. It has also been quoted from Piedmont and several other countries. 4. It is a valuable mineral for the preparation of blue enamel colours, but particularly for smalt, and forms an important object in some of the mining districts of Saxony. 5. The Grey Cobalt-Ore (JAM. Syst. Vol. III. p. 287), which is considered by HAUY as a variety of the present species, and the Radiated White Colalt (Id. ibid. p. 286), will probably require in future to be established into a separate species. They are, however, too imperfectly known at pre- sent to enable us to determine their place in the order Py- rites. From several imitative shapes in which it occurs, the regular forms of this species seem to belong to the prismatic system, among which are very thin four-sided ORDEttX. HEXAHEDUAL COBALT-PYRITES. 455 tabular prisms, sometimes disengaged from contact with others. It occurs generally, however, in reniform or glo- bular compositions, consisting of very thin columnar indi- viduals ; the individuals of its granular compositions are often impalpable, the fracture being uneven, flat conchoidal, sometimes even. The surface of the imitative shapes is rough, drusy, or granulated, and subject to tarnish ; so are also the faces of fracture, which assume in tune a dark grey colour. Their metallic lustre is united to a more or less dark steel-grey colour, inclining to tin-white in the radiated varieties, but which becomes blackish in the streak, and as- sumes a slight degree of lustre. It is brittle, its hardness is = 5-5, and the specific gravity of a radiated variety = 7 '280, of a compact variety = 7-064 ; the ktter ought per- haps to be larger, on account of the numerous interstices in the compound mass. According to JOHN, the radiated white Cobalt consists of Cobalt 28-00. Arsenic 65 '75. Iron, with Manganese 6-25. Its mixture may be expressed by Fe As2 4- 2 Co As + 2 Co As2, which gives the ratio among the above men- tioned metals = 26-46 : 67-46 : 6-08. The locali ty of the radiated variety is Schneeberg in Sax- ony ; the compact ones are found at the same place, but also at Annaberg, Joachimsthal, in the district of Siegen, &c. The Cornish variety probably also belongs to this spe- cies. It is preferred to the octahedral Cobalt-pyrites hi the smalt manufactures. 2. HEXAHEDBAL COBALT-PYKITES. Hexahedral Cobalt-Pyrites or Silver- White Cobalt. JAM. Syst. VoL III. p. 279. Man. p. 269. Bright White Cobalt. PHILL. p. 278. Glanz-Kobold. WERN. Hoffm. H. B. IV. 1. S. 186. Kobaltglanz. HAUSM. I. S. 157. Kobaltglanz. LEOXH. S. 297. Cobalt gris. HAUY. Traite', T. IV. p. 204. TabL comp. p. 107. Traite', 2de Ed. T. IV. p. 225. 456 PHYSIOGRAPHY. CLASS n. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (P, M) ; 6 ( Combinations. 1. R — co. P -|- QD. 2. R— oo. P. P -f OD. Sim. Fig. 112. Inclination of P on a = 135° ; of P on e = 102° 13', BOUENON. Cleavage, R — oo perfect ; P -fc- GO less distinct. Fracture small and imperfect conchoidal. Sur- face rougb, particularly P + oo, sometimes also horizontally streaked. Subject to tarnish. Lustre metallic. Colour intermediate between bronze-yellow and copper-red. Streak dark greyish-black. Slight action on the magnet. Brittle. Hardness = 3-5 ... 4-5; Sp. Gr = 4-631, of a cleavable variety. Compound Varieties. Massive: composition granular, individuals of various sizes, or even im- palpable. Fracture uneven. OBSERVATIONS. 1. The varieties of the present species have been divid- ed into Foliated and Common Magnetic Pyrites, which are easily distinguished from one another, as their division depends upon one single character, the presence of cleavage in the former, and the want of it in the latter, on account of the too small size of the component individuals. 2. One analysis by HATCHETT, and two by STROME.YER, have yielded the following proportions : Iron 63-50 59-85 5S-37. Sulphur 36-50 40-15 43-63. The first of these is expressed by Fe S2, which contains 62'77 iron, and 37*23 sulphur ; the others are considered- ORDER X. OCTAHEDRAL COPPER-PYRITES. 467 as mixtures «f the two sulphurets. In other respects it differs little from the two preceding species. It is often formed in slags. 3. It occurs in beds along with other minerals contain- ing iron, with dodecahedral Garnet-blende, &c. It forms an accidental ingredient of several rocks, and crystallises in their fissures. Its presence has also been ascertained in several meteoric stones. 4. The locality of some large and distinct crystals, pre- «erved in some of the Vienna collections, is not known. Small crystals are found at Andreasberg in the Hartz. The compound varieties occur more plentifully. There are cleavable ones at Bodenmais in Bavaria, and various others at Breitenbrunn and Geyer in Saxony, at Gieren and Querbach in Silesia, in the Hartz, in several districts of Stiria, particularly at Obedach, in Cornwall and other countries. 5. It does not seem as if anywhere the rhomhohedral Iron-pyrites alone were employed to any use ; but as it occurs often along with the hexahedral Iron-pyrites, it is used for the same purposes. GENUS V. COPPER-PYRITES. 1. OCTAHEDRAL COPPER-PYRITES. Variegated Copper. JAM. Syst. Vol. III. p. 334. Man. p. 278. Buntkupfererz. Purple Copper. PHILL. p. 299. Buntkupfererz. WERN. Hoffm. H. B. III. 2. S. 110. Bunter Kupferkies. HAUSM. I. S. 163. Bunt- Kupfererz. LEONH. S. 256. Cuivre pyriteux he'pa- tique. HAUY. Traite', T. III. p. 536. Tabl. comp. p. 86. Traitd, 2de Ed. T. III. p. 436. Fundamental form. Hexahedron. Vol. I. Fig. 1. Simple forms. H (a) ; O (P). Char, of Comb. Tessular. Combination. H. O., Vol. I. Figs. 3. and 4, Cornwall, 468 PHYSIOGRAPHY. CLASS II. Cleavage, traces in the direction of the octahedron, Fracture small conchoidal, uneven. Surface ge- nerally rough, particularly the hexahedron, and often curved, much subject to tarnish. Lustre metallic. Colour intermediate between copper-red and pinchbeck-brown. Streak pale greyish-black, a little shining. Rather sectile. Hardness = 3-0. Sp. Gr. = 5*003, from the Bannat. Compound Varieties. Twin-crystals: axis of revolution perpendicular, face of composition paral- lel to a face of the octahedron, the individuals be- ing continued beyond the face of composition. Fig. 128. Massive : composition granular, strongly con- nected, fracture conchoidal and uneven. OBSERVATIONS. 1. The tessular form of the present species has been first recognised by Mr W. PHILLIPS in very distinct crystals, resembling Fig. 3. (Vol. I.). Generally, however, parti, cularly the larger crystals, are less regularly formed, and grouped in twins resembling those of octahedral Fluor-ha- loide and rhombohedral Kouphone-spar. 2. According to Mr It. PHILLIPS, it consists of Copper 6 1-07. Sulphur 23-75. Iron 14-00. Silica 0-50. The formula Fe S2 + 4 Cu S agrees very nearly with this analysis, giving the proportions of copper, iron, and sul- phur, = 62-67 : 13-44 : 23-89. Before the blowpipe it comports itself very much like pyramidal Copper-pyrites. 3. It occurs in beds and veins, the crystallised varieties ORDER X. PYRAMIDAL COPPER-PYRITES. 4G9 only in veins. It is accompanied chiefly by various other ores of copper. 4. At Orawitza and other places in the Bannat, the oc- tahedral Copper-pyrites occurs in beds, and is very fre- quently associated with dodecahedral Garnet. It is found likewise in beds in the cupriferous shale of the Mansfeld, included in thin layers in the bituminous marl-slate. Seve- ral of the Saxon veins contain varieties of it ; but it is par- ticularly found in Cornwall, which contains the only loca- lities where crystals have been discovered, in the vicinity of Redruth. In smaller quantities it is found also in Ireland, Hessia, Silesia, in Norway and Sweden, in Greenland, &c. 5. It is a valuable mineral for extracting copper. 2. PYRAMIDAL COPPER-PYRITES. Octahedral Copper-Pyrites or Yellow Copper. Pyrites. JAM. Syst. Vol. III. p. 310. Pyramidal Copper-py- rites. Man. p. 275. Copper Pyrites. Yellow Copper Ore. PHILL. p. 302. Kupferkies. WERN. Hoffrn. H. B. III. 2. S. 113. Genieiner Kupferkies. HAUSM. I. S. 1C2. Kupferkies. LEONH. S. 258. Cuivre pyriteux. HAUY. Traite', T. III. p. 529. TabL comp". p. 85. Traite', 2de Ed. T. III. p. 432. HAIDINGER. Mem. Wern. Soc. VoL IV. p. 1. PHILL. Ann. of PhiL Vol. III. p. 296. Fundamental form. Isosceles four-sided pyramid. P = 109° 53', 108° 4(X. Vol. I. Fig. 8. R. G. Simple forms. P — CD (a) ; P — 4 (d) = 155° 6', 38° 25'; P — 2 = 132° 19', 69° 44' ; P — 1 (b) = 120° 3(7, 89° 9/ ; P (P F) Alston, Cum- berland ; P + 1 (c) = 101° 49/, 126° 11' ; P + 2 = 96° 33', 140° 31' ; P + x ; ^ P — 3 (e) = 146° 20', 49° 5 _ O T> 4.P— -oo. ~ E5, _. i*ip_ 2. P— 1. — 4 iP — 3 _A_p. p + i — t_Li — IZL/ z V 3 A J-TA. ^ —7;: tH±lnrL. — £. Fig. 178.* Inclina- 2 2 tion of /on /over e = 155° 35'. * Cleavage, P + l, sometimes very perfect, but in- terrupted ; P — oo indistinct. Fracture con- choidal, more or less perfect. Surface P — 1 generally horizontally streaked. The alternat- ing enlarged faces of P are irregularly streaked parallel to the edges of combination with P + l, and often uneven; the other faces of P are faint- ly but regularly streaked in the same direction, and much more smooth. The remaining faces are almost all smooth, and often possess a high lustre. Lustre metallic. Colour brass-yellow. Streak greenish-black, a little shining. Rather sectile. Hardness = 3-5 ... 4-0. Sp. Gr. = 4-169. f A fine crystal of this form is in the cabinet of Mr ALLAN. H- ORDEttX. PYRAMIDAL COPPER-PYRITES. 471 Compound Varieties. Twin-crystals : face of composition parallel, axis of revolution perpendicu- lar to a face of P, similar to the composition of the octahedron. Fig. 156; 2. Face of composition per- pendicular, axis of revolution parallel to a terminal edge of P -f 1. This law is complementary to the preceding one ; 3. Face of composition perpendi- cular, axis of revolution parallel to one of the ter- minal edges of P. These three kinds of regular composition are not only often repeated in parallel layers, and contiguous to the different homologous parts of the crystals, but they are even found to take place at the same time. Globular, reniform, botryoidal, stalactitic, and other imitative shapes : surface generally rough, sometimes also smooth, composition impalpable, fracture flat conchoidal. Massive : composition granular, of various sizes of individuals, often impalpable, and commonly strong- ly coherent, fracture uneven or flat conchoidal. OBSERVATIONS. 1. Pyramidal Copper-pyrites has been found to contain Copper 30-20 30-50 41-00 32-00 34-40 33-12. Iron 32*30 33-00 17*00 34-00 30-47 30-00. Sulphur 37-00 35-00 45-CO 33-00 33-87 3TJ-52. Silica 0-00 0-00 0-00 0-00 0-27 0-39. GUENIVEAU. L.AMPAD. BREITH. H. ROSE. Upon charcoal ft becomes black before the blowpipe, and red on cooling. It melts into a globule, which becomes magnetic if kept in the blast for some time. With borax it yields a globule of copper. It is partly soluble in dilute nitric acid ; the solution is green, and the undissolved park consists of sulphur. PHYSIOGRAPHY. CLASS II. 2. Pyramidal Copper-pyrites is equally frequent in beds and veins. In beds it is accompanied by various ores of iron and copper, by hexahedral Lead-glance, dodecahedral Garnet-blende, several species of Augite-spar, &c. ; in veins it is found along with a great variety of different species, among which, besides the preceding ones, we notice several ores of silver, as hexahedral Silver-glance, &c. It often occurs accompanying pyramidal Tin-ore and prismatic Scheelium- ore. The black friable substance called Copper-black, is the product from the decomposition of pyramidal Copper-py- rites, but also from that of several other species. If pure, it is the peroxide of copper. 3. Pyramidal Copper-pyrites is found in many countries. It occurs in veins in Saxony, particularly in well defined crystals in the mine of Kurprinz near Freiberg, also in Anhalt, in the Hartz, and particularly in very large quan- titic s in Cornwall. In beds it is found in the Bannat of Temeswar, in the county of Gomb'r, and other districts in Hungary, in Stiria, in Thuringia and Mansfeld, and pro- bably also in Anglesea, where large quantities of it occur. Much pyramidal Copper-pyrites is also met with in Nor- way, Sweden, Siberia, &c. That from the Uammelsberg near Goslar in the Hartz forms an intimate, and often nearly impalpable mixture with hexahedral Lead-glance, dodecahedral Garnet-blende, and hexahedral Iron-pyrites, and occurs in the shape of a bed in grey wacke. 4. Pyramidal Copper-pyrites is a very important mineral for the production of Copper. It is also used for obtaining blue vitriol or sulphate of copper. END OF THE SECOND VOLUME. OF THE UNIVERSITY URN CIRCULATION DEPARTMENT 202 Main Library ^N PERIOD 1 OME USE 2 3 i 5 6 kLL BOOKS MAY BE RECALLED AFTER 7 DAYS 3 AND RECHARGES WAV CJE MADE 4 DAYS PRIOR TO DUE DATE. !ODS ARE 1 -MONTH. 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