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Full text of "The elements of blowpipe analysis"

UC-NRLF 



B 3 121 fllS 



/BERKELEY 

LIBRARY 

I UNIVERSITY OF 
\CALIFORNIA 



EARTH 






Geology 



THE ELEMENTS OF BLOWPIPE 
ANALYSIS 



THE 

ELEMENTS OF BLOWPIPE 
ANALYSIS 



BY 



FREDERICK HUTTON GETMAN, F.C.S. 

INSTRUCTOR IN CHEMISTRY IN THE STAMFORD 
HIGH SCHOOL 



godt 
THE MACMILLAN COMPANY 

LONDON : MACMILLAN & CO., LTD. 
1899 

All rights reserved 




BY THE MACMILLAN COMPANY. 



Nortoonfi 
J. 8. Gushing & Co. - Berwick Sc Smith 
Norwood Mass. U.S.A. 



PREFACE 

THESE few pages are intended to serve 
a twofold purpose, to give the student 
a general outline of Blowpipe Analysis, 
and to introduce him to the methods of 
Determinative Mineralogy. 

Every effort has been made to simplify 
details so that the book may be used in 
both High Schools and Colleges. 

Tables for " systematic " examination have 
been intentionally omitted, for in the au- 
thor's estimation these tend to dull the 
student's power of observation, and to make 
him place little value upon minute details. 

The alphabetic arrangement has been 
followed for the sake of convenience when 
referring to the book. 

819488 



Vi PREFACE 

The last chapter is not intended to serve 
as a key to determining the minerals therein 
described, but rather it is added to give 
the student exercise in Blowpipe Analysis, 
and at the same time to point out the 
methods of Determinative Mineralogy. 

Finally, the author would acknowledge his 
indebtedness to the following works : " Man- 
ual of Qualitative Analysis," Fresenius; 
"Qualitative Chemical Analysis," Venable; 
Roscoe and Schorlemmer's " Treatise on 
Chemistry"; Foye's " Hand- Book of Min- 
eralogy"; Dana's "Mineralogy"; Kobell's 
"Tafeln zur Bestimmung der Mineralien"; 

etc. 

FREDERICK HUTTON GETMAN. 

STAMFORD, CONN., 
Feb. 22, 1899. 



TABLE OF CONTENTS 



CHAPTER I 

PAGE 

Apparatus and Reagents 1-7 



CHAPTER II 

General Outline of Blowpipe Analysis 8 

Definitions 9 

Examination on Charcoal Alone 10 

Examination on Charcoal with Sodium Carbonate . . 13 

Examination in Tube with Sodium Carbonate and Charcoal . 15 

Examination on Platinum Wire 16 

Examination in Borax Bead 17 

Examination with Cobalt Nitrate 20 

CHAPTER III 

General Reactions for the Detection of the Metallic Ele- 
ments in Simple Compounds 22 

Aluminum 23 

Antimony 24 

Arsenic 25 

Bismuth - . ' , 25 

Cadmium 26 

Chromium 26 

Cobalt .......... 27 

vii 



viii CONTENTS 

PAGE 

Copper 28 

Iron 28 

Lead 29 

Manganese 30 

Mercury 30 

Nickel 31 

Silver 32 

Tin 32 

Zinc 33 

The Alkali Metals 34 

Ammonium 34 

Potassium 35 

Sodium 35 

Lithium 36 

The Alkaline Earths 36 

Barium 36 

Calcium 37 

Strontium 37 



The Acid Elements 



37 



Borates 37 

Bromides 38 

Chlorides 38 

Fluorides 38 

Iodides 39 

Nitrates 39 

Phosphates 40 

Silicates . . . .40 

Sulphides . .41 



CONTENTS IX 
CHAPTER IV 

PAGE 

Behavior of Some of the Principal Ores before the Blowpipe 43 

Ores of Antimony '.. . . 46 

Ores of Arsenic . . . . "* . . . -47 

Ores of Bismuth . , . . . . . . 48 

Ores of Chromium 49 

Ores of Cobalt 50 

Ores of Copper , , 52 

Ores of Iron 57 

Ores of Lead 60 

Ores of Manganese 63 

Ores of Mercury 64 

Ores of Nickel 65 

Ores of Silver 66 

Ores of Tin i . . 69 

Ores of Zinc 70 

COMPARATIVE TABLES 

I. Colors of Coatings on Charcoal 73 

II. Flame Colorations , ' 9 73 

III. Colors of Borax Beads in oxidizing Flame ... 74 

IV. Colors of Borax Beads in reducing Flame ... 75 
V. Colors of Microcosmic Salt Beads in oxidizing Flame . 76 

VI. Colors of Microcosmic Salt Beads in reducing Flame . 77 




FORCEPS 
Fig. 5 



AGATE MORTAR & PESTLE 
Fig. 4 




HAMMER 
Fig, 6, 









3 -CORNERED FIJ_ES 
Fig, 7 



BLOWPIPE ANALYSIS 

CHAPTER I 

THE blowpipe was first applied to mineral 
analysis in 1733 by Anton Swab, and its 
applications have since been improved and 
extended by various chemists, among whom 
may be mentioned Bergmann, Cronstedt, 
Gahn, Berzelius, and Plattner. 

Blowpipe. The common blowpipe of the 
jeweller is not particularly well suited to 
the operations of blowpipe analysis, since 
the flame has often to be kept playing 
upon the assay for some time, and the 
condensed moisture of the breath would 
seriously interfere with the passage of the 



BLOWPIPE ANALYSIS 

air through the jet. One of the best and 
least expensive forms of blowpipe is shown 
in Fig. i. This consists, as is seen from 
the illustration, of a conical-shaped tube of 
tin closed at the wide end and formed into 
a mouthpiece at the small end; soldered 
into the tube at the large end, and at 
right angles to its axis, is a small brass 
tube which terminates in a conical tip 
pierced with a very fine hole. With this 
pipe it is possible to perform all of the 
operations of mineral analysis. 

Some little practice is necessary to keep 
the flame steady and to take the breath at 
the same time. 

No rule can well be given to the begin- 
ner, but his experience becomes his best 
guide. 

Bunsen Flame. Any kind of flame can 
be used for the blowpipe, provided it be 



BUNSEN FLAME 3 

not too small ; but since almost every labo- 
ratory to-day is furnished with gas and the 
Bunsen burner (Fig. 2), it will only be 
necessary to describe the use of the flame 
from this source. Upon examining the 
Bunsen flame with care, it will be seen that 
the flame consists of three distinct parts. 

A dark inner cone which consists of gas 
not yet raised to the ignition point. Be- 
yond this there is a luminous cone, where 
combustion is incomplete owing to lack of 
oxygen, and outside of this we find the 
non-luminous cone where the gas is com- 
pletely burned. 

This outer envelope is the hottest por- 
tion of the flame, and is known as the 
" oxidizing " flame because there is an excess 
of oxygen which is imparted to substances 
placed therein. 

The luminous cone is known as the 
"reducing" flame, for in it metallic oxides 



4 BLOWPIPE ANALYSIS 

are reduced, the oxygen being taken up 
by the small incandescent particles of car- 
bon. 

If the air-holes at the base of the Bun- 
sen burner be opened, the two inner cones 
become elongated, and the flame appears 
almost colorless. 

The blowpipe enables us to get an oxidiz- 
ing and a reducing flame of better form 
and greater power. To do this we cut off 
the air supply at the base of the burner 
and turn off the gas until the flame is 
about i cm. high; then upon introducing 
the blowpipe, and blowing a strong con- 
tinuous jet of air across the Bunsen flame, 
we produce an oxidizing flame about 4-5 
cm. in length. If the tip of the blowpipe 
be held outside of the Bunsen flame, and 
the pressure of the stream of air be dimin- 
ished, we obtain a reducing flame. 



BUNSEN FLAME 5 

Supports. For supports, charcoal, plati- 
num, and glass are chiefly used. The 
charcoal should be made from some light 
wood, such as alder. It should be well 
burnt, and should not scintillate or smoke. 

The platinum supports are generally in 
the form of wire and foil. Platinum-tipped 
forceps are frequently employed in blow- 
pipe analysis. 

Glass is used in the form of tubing. 

Hard glass tubing, 3 mm. bore, is drawn 
off into ignition tubes 7-8 cm. in length. 
Several dozen of these tubes should be 
made before commencing the tests of the 
next chapter. 

Apparatus. A small agate mortar, 4-5 
cm. in diameter, should be provided in 
which to grind the samples to be exam- 
ined. 

The pestle, which should also be of agate, 



6 BLOWPIPE ANALYSIS 

must be adapted to the mortar in shape 
and size. 

Two pairs of forceps will also be needed. 

One pair should be of steel, and the other 
pair of brass, with fine points. 

Of other apparatus, the most necessary 
is: 

A small hammer and anvil. 

Two three-cornered files. 

Small piece of cobalt glass, about 5 x 10 
cm. 

Pocket magnifying lens. 

Several small watch glasses for metallic 
beads, etc. 

Chemicals. A list of the principal chemi- 
cals is here given : 

Sodium carbonate, Na 2 CO 3 . 

Borax, Na 2 B 4 O 7 + ioH 2 O. 

Microcosmic salt, (HNaNH 4 ), PO 4 + 8 H 2 O. 



BUNSEN FLAME 7 

Cobalt nitrate, Co(NO 3 ) 2 +5 H 2 O. 
Potassium cyanide, KCN. 
Hydrochloric acid, (dilute), HCl + nH 2 O. 
Litmus paper, red and blue. 
Brazil-wood paper. 

Any other special reagents which may be 
needed will be mentioned as required. 



CHAPTER II 

GENERAL OUTLINE OF BLOWPIPE ANALYSIS 

[ABBREVIATIONS : O. F. for oxidizing flame, R. F. for reducing flame, 
Ch. for charcoal, Ct. for coating, Bp. for blowpipe.] 

IN order to examine a substance before 
the blowpipe to determine the presence 
or absence of certain elements, it becomes 
necessary to arrange a systematic method. 
As with all branches of chemical work, 
one's success is largely dependent upon 
neatness of manipulation and carefulness of 
observation. 

The following order of observation is 
essentially that given by Berzelius : 

1. Examination on charcoal by itself. 

2. Examination on charcoal with Na z CO 3 . 

8 



GENERAL OUTLINE OF BLOWPIPE ANALYSIS 9 

3. Examination in ignition tube with 
Na 2 CO 8 and charcoal. 

4. Examination on platinum wire. 

5. Examination in borax bead. 

6. Examination with Co(NO 3 ) 2 . 

After having examined a body in these 
six different ways, we shall be able to say 
what are its principal constituents. 

Before describing the method of carrying 
out these six different operations, it will be 
necessary to give a few definitions of terms 
which we shall have frequent occasion to 
employ. 

Definitions. Ignition is the heating of a 
substance to a high temperature. 

Fusion is the heating of a substance to 
the melting-point. 

Intumescence is the swelling of the sub- 
stance upon heating. 



10 BLOWPIPE ANALYSIS 

Decrepitation is the crackling of a sub- 
stance due to the sudden expansion of 
combined water upon heating. 

Deflagration is the burning of a sub- 
stance with explosive violence, generally 
due to excess of oxygen. 

Incandescence is the white light emitted 
by a substance that is infusible when sub- 
jected to a high temperature. 

Examination on Charcoal alone. The size 
of the assay should be about that of a 
mustard seed. This is sufficiently large to 
show all of the reactions clearly, and though 
a larger piece would exhibit the character- 
istic phenomena, yet much more effort is 
required. A very small, shallow hole should 
be cut in the Ch. to receive the assay. The 
Bp. flame should be directed at an angle of 
about 30 with the surface of the Ch. Con- 
siderable care must be taken lest the hole in 



GENERAL OUTLINE OF BLOWPIPE ANALYSIS II 

the Ch. is burned too deep and the assay 
lost in the coal. 

The force of the air from the jet must 
also be borne in mind for a strong blast, or 
sudden puffs may blow the substance away. 

The following changes are to be looked 
for: 

a. Whether the substance is volatile or 
non-volatile. 

Illustrations. Examine before the Bp. on 
Ch. some arsenious oxide, As 2 O 3 , also some 
alumina, A1 2 O 3 . 

b. Whether the substance is fusible or 
infusible. 

Illustrations. Examine before the Bp. on 
Ch. some silver oxide, AgO, also some zinc 
oxide, ZnO. 

c. Whether the substance is alkaline or 
non-alkaline when placed upon moistened 
red litmus. 



12 BLOWPIPE ANALYSIS 

Illustrations. Ignite some calcium car- 
bonate, CaCO 3 , before the Bp. on Ch., and 
place residue on moistened red litmus. In 
like manner, examine some magnesium car- 
bonate, MgCO 3 . 

d. Color of coating on Ch. caused by 
combination of metal and oxygen due to 
heat of Bp. flame. 

Illustrations. Examine some oxide of 
lead, PbO, before the Bp. on Ch., also some 
oxide of cadmium, CdO. 

e. Decrepitation. 

Illustration. Examine some sodium chlo- 
ride, NaCl, before the Bp. on Ch. 

f. Deflagration. 

Illustrations. Examine some potassium 
nitrate, KNO 3 , before the Bp. on Ch., also 
some ammonium nitrate, NH 4 NO 3 . 



GENERAL OUTLINE OF BLOWPIPE ANALYSIS 13 

g. Intumescence. 

Illustration. Examine some alum, 

K 2 A1 2 (S0 4 ) 4 , : 

before the Bp. on Ch. 

h. Incandescence. 

Illustration. Examine some oxide of 
barium, BaO, before the Bp. on Ch. 

i. Formation of a metallic bead color 
and malleability. 

Illustration. Examine some silver oxide, 
AgO, before the Bp. on Ch. 

Examination on Charcoal with Na 2 C0 3 . 

Metallic compounds are often difficult to 
reduce with the blowpipe flame alone, and 
hence no bead is obtained. In order to 
facilitate reduction and the obtaining of a 
metallic bead, the substance in a finely 
powdered condition is mixed with four 



14 BLOWPIPE ANALYSIS 

parts of sodium carbonate, Na 2 CO 3 , and 
ignited before the Bp. on Ch. The me- 
tallic compound is decomposed, the metal 
being transformed into the carbonate, which 
in turn, through the agency of the Ch. and 
the heat of the flame, is reduced to the 
free metal. Sometimes the reduction is 
made easier by adding to the substance 
about its own bulk of potassium cyanide, 
KCN, which takes up oxygen from the 
compound and is converted into potassium 
cyanate, KCNO. 

The reactions in reducing copper sul- 
phate, CuSO 4 , with Na 2 CO 3 and with KCN 
before the blowpipe, are here given : 

CuS0 4 + Na 2 C0 3 = CuC0 3 + Na 2 SO 4 1 
2 CuCO 3 + C = 3 CO 2 + 2 Cu J 

CuSO 4 + Na 2 CO 3 = CuCO 8 + Na 2 SO 4 
CuO + KCN = Cu + KCNO 



GENERAL OUTLINE OF BLOWPIPE ANALYSIS 15 

After obtaining beads, it is well to obtain 
their coatings, for oftentimes it is only in 
this way that we can distinguish between 
the metals. 

Examination in Tube with Na 2 C0 3 and 
Charcoal. If the substance in a finely 
pulverized condition be mixed with twelve 
parts, Na 2 CO 3 , and six parts of charcoal 
powder and the mixture be placed in an 
ignition tube and subjected to heat, the 
acid of the substance combines with the 
soda and the metal is set free. 

If this metal is volatile, a sublimate is 
formed in the upper end of the tube. 

Mercury deposits in minute globules, 
which may be seen with the magnifying 
glass. Arsenic forms a ring, which, when 
examined with the magnifying glass, is seen 
to be made up of minute crystals. Am- 
monia is recognized by its characteristic 



1 6 BLOWPIPE ANALYSIS 

odor, and also by its turning a slip of 
moistened red litmus (held over the mouth 
of the tube) blue. 

Examination on Platinum Wire. Many 
substances possess the property of impart- 
ing to the colorless flame of the Bunsen 
burner characteristic colors. 

The chlorides of these substances exhibit 
these flame reactions best, and hence before 
applying the flame tests we dip the wire 
which serves as a support into hydrochloric 
acid and then into the substance. When 
the substance has been taken up on the 
wire, it is placed in the edge of the long 
colorless flame of the Bunsen burner near 
the apex, when instantly the flame becomes 
tinged with the characteristic color of the 
substance. 

Illustrations. Sodium compounds color 
the flame yellow, and a crystal of potas- 



GENERAL OUTLINE OF BLOWPIPE ANAL YSIS I / 

sium dichromate appears colorless in the 
sodium light. 

This sodium reaction is extremely deli- 
cate, it being possible to detect with ease 
a quantity of a sodium salt less than 
innnhnnr of a milligram in weight. 

Potassium colors the flame purplish-violet. 

Barium colors the flame apple-green. 

Strontium colors the flame crimson. 

Calcium colors the flame orange-red, dis- 
tinguished from strontium, by appearing 
gray when seen through blue glass. 

Boracic acid colors the flame green when 
the substance has been moistened with 
glycerine. 

Examination in Borax Bead. Borax, 
Na 2 B 4 O 7 , and microcosmic salt, 

NaNH 4 H . P0 4 , 
possess the property of dissolving many of 



1 8 BLOWPIPE ANALYSIS 

the metallic oxides at the temperature of 
the Bunsen flame. 

For example, with oxide of cobalt, the 
following reactions take place with the two 
fluxes : 

CoO + Na 2 B 4 O T = Co(BO 2 ) 2 + 2 NaBO 2 . 

On heating, NaNH 4 H.PO 4 , it is decom- 
posed into the metaphosphate of sodium, 
NaPO 8 , 

CoO + NaPO 3 = CoNaPO 4 . 

Now in such cases of solution the me- 
tallic oxides impart a characteristic color 
to the flux. 

The platinum wire is the best support, 
it is heated to incandescence in the Bunsen 
flame, and then is quickly dipped into the 
borax, when a small globule will adhere, 
this is removed to the flame again when 
the borax melts to a clear glassy bead. 
While the bead is still melted, touch it to 



GENERAL OUTLINE OF BLOWPIPE ANALYSIS 1 9 

the finely pulverized substance and replace 
in the flame. In a few seconds the small 
particles of the substance will have dis- 
solved, and the bead will be seen to have 
assumed the color characteristic of the sub- 
stance. Note the color when hot and then 
when cold ; often there is a wide difference. 
Then, too, the test should be made in both 
O. F. and R. F. 

Some analysts prefer to make a small 
loop in the end of the wire before taking 
up the borax to make the bead. Care 
should be taken to see that the bead is 
colorless before bringing it in contact with 
the substance. 

As the depth of color produced is largely 
dependent upon the amount of substance 
taken, some little caution should be exer- 
cised to insure taking up about the same 
quantity each time. 

Illustrations. Make several beads, and 



20 BLOWPIPE ANALYSIS 

note the colors characteristic of the follow- 
ing oxides: cobalt, nickel, iron, manganese, 
chromium, and copper. 

The microcosmic salt bead dissolves al- 
most every oxide except silica, SiO 2 , and 
this is seen to float about in the melted 
mass. This is used as a test for silica. 

Examination with Co(N0 3 ) 2 . If after ex- 
amination on the Ch. per se, a white infusible 
residue remains, it is moistened with a drop 
of cobalt nitrate Co(NO 3 ) 2 and re-ignited 
before the Bp., when a change of color will 
be observed. This change in color is owing 
to the fact that the heat of the Bp. flame 
decomposes the cobalt nitrate, nitric acid 
being driven off, and the remaining CoO 
forming with the oxide of the residue a 
colored mass. 

Illustrations. Ignite before the Bp. on 
Ch. the following oxides, allow to cool, 



GENERAL OUTLINE OF BLOWPIPE ANALYSIS 21 

add a drop of Co(NO 8 ) 2 , re-ignite, and note 
color, aluminum, magnesium, zinc, and 
calcium. 

Care should be taken to thoroughly ignite 
before adding the cobalt nitrate solution. 

With the six methods of examination just 
given almost every simple substance can be 
detected, but should any doubt remain, a 
few simple tests in the " liquid way " will be 
sufficient to substantiate the blowpipe exam- 
ination. 



CHAPTER III 

GENERAL REACTIONS FOR THE DETECTION OF THE 
METALLIC ELEMENTS IN SIMPLE COMPOUNDS 

FOR the sake of convenience, rather than 
for scientific reasons, the following com- 
pounds have been arranged in alphabetic 
order. Also the oxides of the elements have 
been taken, since they exhibit the reactions 
to best advantage. 

The student should work through care- 
fully each one of the tests and satisfy him- 
self as to the characteristic reactions of the 
various elements, for only in this way can 
he expect to recognize the substances when 
presented to him as " unknowns." It is 
advisable to provide a note-book and rule 
it as follows : 

22 



GENERAL REACTIONS 



BEHAVIOR OF SUBSTANCE 


Before Bp. 
onCh. 
alone 


Before Bp. 
on Ch. with 
NajCO 8 


In ignition 
tube with 
Na 2 CO 3 and 
Ch. 


In flame on 
platinum 
wire 


In flame 
with borax 
bead 


After first 
ignition 
with 
Co(NO 3 ) 2 






- 








Remar 
Substa 


ks 


nee __ 





i. Aluminum, AL0 3 . Before the Bp. on 
Ch. Infusible. No change. 

Before the Bp. on Ch. with Na 2 CO 8 . 
Forms an infusible compound with slight 
intumescence. 

In ignition tube with Na 2 CO 3 and Ch. 
No change. Moisture driven off. 

In flame on platinum wire. No change. 
Becomes incandescent. 

In flame with borax bead. In O. F. 



24 BLOWPIPE ANALYSIS 

dissolves slowly, forming a colorless glass 
which remains so on cooling. 

With Co(NO 3 ) 2 . Mass becomes blue upon 
re-ignition. 

2. Antimony, Sb 2 3 . Before the Bp. on 
Ch. In O. F. volatilizes without change. 
In R. F. is reduced and volatilized. White 
coating of antimonious oxide deposited on 
Ch. Blue tinge imparted to flame. 

Before the Bp. on Ch. with Na 2 CO 3 . 
Readily reduced. ' White brittle bead. Very 
volatile, giving characteristic white coat- 
ing. 

In ignition tube with Na 2 CO 3 and Ch. 
Volatilized. 

In flame on platinum wire. Volatilized. 
Colors flame greenish blue. 

With borax bead on platinum wire. In 
O. F. dissolves to a colorless glass. 

With Co(N0 3 ) 2 



GENERAL REACTIONS 2$ 

3. Arsenic, As 2 3 . Before the Bp. on Ch. 
Very volatile. Strong garlic odor to fumes. 

Before the Bp. on Ch. with Na^COs. 
Reduced with emission of arsenical fumes. 

In ignition tube with Na 2 CO 3 and Ch. 
Volatilizes, forming a mirror-like deposit 
of metallic As in the cooler part of tube. 

In flame on platinum wire 

With borax bead on platinum wire 

With Co(N0 3 ) 2 _. 



4. Bismuth, Bi 2 3 . Before the Bp. on 
Ch. Yields a coating orange-yellow 
when hot, lemon-yellow when cold. The 
yellow coating usually has a white outline. 

Before the Bp. on Ch. with Na 2 CO 3 . 
Easily reduced to metallic bismuth. Yellow 
bead brittle, but less so than antimony. 

In ignition tube with Na 2 CO 3 and Ch. 



26 BLOWPIPE ANALYSIS 

In flame on platinum wire 

With borax bead on platinum wire. 
In O. F. small quantity dissolves to a clear 
yellow glass, which becomes colorless when 
cold 

With Co(NO 3 ) 2 _.. ._ 

5. Cadmium, CdO. Before the Bp. on 
Ch. Gives a coating on the coal. Red- 
dish-brown when cold. Very volatile. 

Before the Bp. on Ch. with Na 2 CO 3 . 
Readily reduced. The metal volatilizes 
easily, giving the characteristic coating. 

In ignition tube with Na 2 CO 3 and Ch. 

In flame on platinum wire 

With borax bead. In O. F. dissolves to a 
clear yellowish bead, colorless when cold. 
With Co(N0 8 ) 2 

6. Chromium, Cr 2 3 . Before the Bp. on 
Ch. No change. 



GENERAL REACTIONS 2/ 

Before the Bp. on Ch. with Nc^COg. 
Cannot be reduced. Soda sinks in Ch. 
and a green colored mass remains. 

In ignition tube with Na 2 CO 3 and Ch. 

In flame on platinum wire 

With borax bead. Dissolves slowly but 
colors intensely. Yellow while hot, green 
when cold. 

With microcosmic salt bead. Colors red 
when hot, green when cold. 

With Co(NO 3 ) 2 

7. Cobalt, CoO. Before the Bp. on Ch. 
In O. F. unchanged. In R. F. is reduced 
to the metal and is magnetic. 

Before the Bp. on Ch. with Na^COg. 
Reduced to a gray magnetic mass. 

In ignition tube with Na^COa and Ch. 

In flame on platinum wire 



28 BLOWPIPE ANALYSIS 

With borax bead on platinum wire. 
In O. F. colors very intensely blue, both hot 
and cold. 

With Co(NO 3 ) 2 

8. Copper, CuO. Before the Bp. on Ch. 
Fuses to a black globule, which can be 
reduced with some difficulty. 

Before the Bp. on Ch. with Na 2 CO 3 . 
Readily reduced to metallic bead, which is 
red in color, hard, malleable. 

In ignition tube with Na 2 CO 3 and Ch. 

In flame on platinum wire. Colors flame 
emerald-green. 

With borax bead on platinum wire. In 
O. F. green when hot, blue when cold. 

With Co(N0 3 ) 2 

9. Iron, Fe 2 3 . Before the Bp. on Ch. 
In O. F. unchanged. In R. F. becomes 
black and magnetic. 



GENERAL REACTIONS 29 

Before the Bp. on Ch. with Na 2 CO 3 
Reduced to a metallic powder, magnetic. 
In ignition tube with Na 2 CO 3 and Ch. 

In flame on platinum wire 

With borax bead on platinum wire. 
In O. F. red while hot, yellow when cold. 
With Co(NO 3 ) 2 

10. Lead, PbO. Before the Bp. on Ch. 
Easily reduced to the metal, bead very 
malleable. Coating yellow, surrounded by 
white ring. 

Before the Bp. on Ch. with Na^COg. 
Instantly reduced. Coats the Ch. upon 
further blowing. 

In ignition tube with Na 2 CO 3 and Ch. 
Reduced to the metal. 

In flame on platinum wire. Tinges 
flame blue. 

With borax bead on platinum wire. 



30 BLOWPIPE ANALYSIS 

In O. F. dissolves easily, forming a limpid 
glass. 

With Co(N0 3 ) 2 

11. Manganese, Mn 2 3 . Before the Bp. 
on Ch. At high temperature turns red. 

Before the Bp. on Ch. with Na 2 CO 3 . Is 
not reduced. 

Before the Bp. in O. F. on platinum foil 
with -NagCOg. Transparent green mass 
when hot. Opaque, bluish-green when cold. 

In ignition tube with Na 2 CO 3 and Ch. 
Not reduced. 

In flame on platinum wire 

With borax bead on platinum wire. In O. F. 
violet-red while hot, amethyst-red when cold. 

With Co(N0 3 ) 2 

12. Mercury, HgO. Before the Bp. on 
Ch. Instantly reduced. Very volatile. 

Before the Bp. on Ch. with Na 2 CO 3 . Re- 
duced and volatilized. 



GENERAL REACTIONS 31 

In ignition tube with Na. 2 CO 3 and Ch. 
Sublimes condensing in the upper part of 
the tube as a metallic ring which is seen 
with the lens to consist of minute globules 
of mercury. 

In flame on platinum wire 

With borax bead on platinum wire 

WithCo(N0 3 ) 2 __ 



13. Nickel, NiO. Before the Bp. on Ch. 
In O. F. unchanged. In R. F. reduced to 
metal, slightly magnetic. 

Before the Bp. on Ch. with Na 2 CO 8 . 
Easily reduced to the metal. 

In ignition tube with Na 2 CO 3 and Ch. 

In flame on platinum wire 

With borax bead on platinum wire. In O.F. 
violet while hot, reddish-brown when cold. 
With Co(NO 3 ) 2 ._ 



32 BLOWPIPE ANALYSIS 

14. Silver, AgO. Before the Bp. on Ch. 
Easily reduced to the metal. White, mal- 
leable, hard bead. Coats the coal dark red 
near assay. 

Before the Bp. on Ch. with Na 2 CO 3 . In- 
stantly reduced to metallic globule. 

In ignition tube with Na 2 CO 3 and Ch. 
Reduced to the metal. 

In flame on platinum wire 

With borax bead on platinum wire. In 
O. F. partially dissolved. Bead becomes 
milk-white. 

With Co(NO 3 ) 2 

15. Tin, Sn0 2 . Before the Bp. on Ch. 
Coats the coal yellow while hot, dirty 
white when cool. Not reduced. 

Before the Bp. on Ch. with Na 2 CO 3 . Re- 
duced to metallic tin. White, hard, mal- 
leable bead. Coating white and close to 
assay. 



GENERAL REACTION'S 33 

In ignition tube with Na 2 CO 8 and Ch. 

In flame on platinum wire 

With borax bead on platinum wire. In 

O. F. small quantity dissolves to limpid 

glass. 

With Co(NO 3 ) 2 . Greenish-blue color. 

1 6. Zinc, ZnO. Before the Bp. on Ch. 

Upon ignition becomes yellow. Is not 
reduced. 

Before the Bp. on Ch. with Na 2 CO 3 . Re- 
duced to metal. Rapidly volatilized, coating 
the coal white. 

In ignition tube with Na 2 CO 3 and Ch. 

In flame on platinum wire 

With borax bead on platinum wire. In 
O.F. yellow while hot, limpid glass when 
cold. 

* 

With Co(NO 3 ) 2 . Green mass. 



34 BLOWPIPE ANALYSIS 

Having now given the principal reactions 
for the most important metals, we will pro- 
ceed to the examination of the alkali metals, 
the alkaline earths, and some of the acid 
elements. 

THE ALKALI METALS 

17. Ammonium, NH 4 . This hypotheti- 
cal compound is commonly classed among 
the alkali metals from its close resemblance 
to the members of this group. 

To detect the presence of this hypotheti- 
cal metal, mix the assay with about four 
parts of Na 2 CO 3 , place in an ignition tube, 
and apply heat. The odor of the evolved 
gas will be recognized, and if a piece of 
red litmus paper be moistened and held at 
the mouth of the tube, it will be turned 
blue by the escaping ammonia gas. 

We are not authorized to infer the pre- 
existence of ammonium, however, from the 



GENERAL REACTIONS 3$ 

appearance of this reaction, for the pres- 
ence of nitrogenous organic matter in the 
substance, which would be decomposed by 
this treatment, would give rise to such a 
reaction. 

1 8. Potassium. Potassium is recognized 
by the color which its salts impart to the 
Bunsen flame. If a portion of a salt of 
potassium be held on a platinum wire in 
the flame, it imparts a blue-violet tint 
which rapidly disappears. 

19. Sodium. Like potassium, this alkali 
metal is detected by the color which its 
salts give to the flame. 

If a sodium salt be held on the platinum 
wire in the flame, it imparts an intense 
yellow color. 

The extreme delicacy of this reaction 
has been mentioned elsewhere. The value 



36 BLOWPIPE ANALYSIS 

of this test is really lessened by its great 
delicacy, for it is possible to detect minute 
quantities of sodium in almost all sub- 
stances, although it may not be in chemi- 
cal combination. As an example, draw the 
platinum wire between the fingers, and 
then place in flame, and note presence of 
sodium. 

20. Lithium, Li 2 0. In the Bunsen flame 
on the platinum wire it imparts a carmine- 
red tinge. 

Hydrochloric acid on the sample aug- 
ments the coloration. 

THE ALKALINE EARTHS 

21. Barium, BaO. In the Bunsen flame 
on the platinum wire it imparts an apple- 
green coloration. This reaction is intensi- 
fied by moistening the sample with hydro- 
chloric acid. 



GENERAL REACTIONS 37 

22. Calcium, CaO. In the Bunsen flame 
on the platinum wire it imparts an orange- 
red color, which appears gray when seen 
through blue glass. 

Hydrochloric acid on the sample makes 
the color more intense. 

23. Strontium, SrO. In the Bunsen 
flame on the platinum wire it imparts an 
intensely red color, which is increased by 
converting the substance into the chloride. 

THE ACID ELEMENTS 

24. Borates. If the substance be finely 
powdered, moistened with glycerine, and 
then placed on a platinum wire in the 
Bunsen flame, it imparts a brilliant green 
color. 

If turmeric paper be dipped into a solu- 
tion of a borate, and then be dried at 
1 00 C., it is turned to a peculiar red 



38 BLOWPIPE ANALYSIS 

color. These two reactions are extremely 
delicate. 

25. Bromides. Bromides treated with 
microcosmic salt and oxide of copper on 
platinum wire impart to the flame a greenish- 
blue color, the edges being decidedly green. 

26. Chlorides. Chlorides are treated in 
the same way as bromides. The color 
imparted to the flame is azure-blue. 

To discriminate between bromides and 
chlorides more clearly, the substance is 
mixed with anhydrous potassium bisulphate 
and fused in an ignition tube. 

Bromine and sulphur dioxide are evolved 
(if the substance be a bromide), the tube 
being filled with a yellow gas possessing 
the characteristic odor of bromine. 

27. Fluorides. A small portion of the 
substance in a finely powdered condition is 



GENERAL REACTIONS 39 

placed in one of the ignition tubes, a strip 
of moist Brazil-wood paper is introduced 
into the open end, and heat is applied. 
Hydrofluoric acid is evolved, and the red 
color of the paper is changed into a straw- 
yellow. 

Mica, containing only 0.75% of fluorine, 
shows the reaction clearly. 

28. Iodides. Iodides are treated, as the 
bromides and chlorides, in a bead of micro- 
cosmic salt with oxide of copper. The 
flame is colored green. 

Fused with potassium bisulphate in an 
ignition tube the violet vapors of iodine 
are evolved, and thus iodides may be dis- 
tinguished from chlorides and bromides. 

29. Nitrates. If a nitrate be heated 
upon charcoal before the Bp., violent defla- 
gration occurs. If the substance contain- 



40 BLOWPIPE ANALYSIS 

ing the nitric acid be mixed with a very 
small quantity of finely powdered potas- 
sium cyanide, the deflagration is accom- 
panied with ignition and detonation. 

If the substance be mixed in a dry 
condition with dry potassium bisulphate, 
and is then heated in an ignition tube, 
red-brown nitrous fumes are evolved. This 
reaction takes place if there is but a small 
quantity of nitrate present. 

30. Phosphates. Phosphates impart to 
the flame a bluish green color. The color 
is made more intense by moistening the 
substance with sulphuric acid, and then 
taking the paste so formed on the plati- 
num wire and placing it in the Bunsen 
flame. 

31. Silicates. Silicates, when treated 
with microcosmic salt on a platinum wire, 



GENERAL REACTIONS 41 

suffer decomposition; the bases unite with 
the phosphoric acid to form a transparent 
glass in which the silica may be seen float- 
ing as a cloudy mass. 

The bead must only be examined for 
silica while hot, since on cooling it becomes 
opaque. 

32. Sulphides. Many sulphides, when 
heated in an ignition tube, volatilize and 
give a sublimate of sulphur in combina- 
tion with the metallic portion of the sub- 
stance. 

A very delicate test for sulphur in what- 
ever combination it may be found in a sub- 
stance, and which may be performed with 
great ease, is to mix the finely powdered 
assay with four parts, Na 2 CO 3 , and fuse in 
an ignition tube. When thoroughly fused 
the tube is broken, and the fused mass is 
placed on a bright silver coin, and a drop 



42 BLOWPIPE ANALYSIS 

of water is added. If the substance con- 
tains sulphur, a black spot will be observed 
on the coin where the fused mass was 
placed. 

Before going on to the next chapter, the 
student should assure himself of his famil- 
iarity with the reactions just given, and he 
should practise with various substances, the 
nature of which is unknown to him. 



CHAPTER IV 

BEHAVIOR OF SOME OF THE PRINCIPAL ORES 
BEFORE THE BLOWPIPE 

FOR the sake of practice, and as a fitting 
introduction to " Determinative Mineralogy," 
this chapter is appended. It is not intended 
to give a detailed account of the minerals, 
but rather to set before the student the 
most marked characters, such as hardness, 
specific gravity, color, lustre, etc. 

To determine the hardness of a mineral, 
we try to scratch it with the minerals 
forming an arbitrary "scale of hardness," 
proceeding successively from the softest to 
the hardest. When we say that a certain 
mineral has hardness = 4, we mean that the 
mineral is scratched by 4 on the scale, and 

43 



44 BLOWPIPE ANALYSIS 

that 4 on the scale is scratched by the 
mineral. The scale of hardness chiefly in 
use is the Mohs-Breithaupt scale, which is 
as follows: 

1. Talc, common laminated light green 
variety. 

2. Gypsum, crystallized. 

3. Calcareous spar, transparent variety. 

4. Fluor spar, crystalline. 

5. Apatite, transparent. 

6. Orthoclase, white cleavable variety. 

7. Quartz, transparent. 

8. Topaz, transparent. 

9. Sapphire, cleavable variety. 
10. Diamond. 

It seldom happens in determining the 
hardness of a mineral that its hardness ex- 
actly conforms to that of some one member 
of the scale. In such cases we generally 
estimate the hardness. For example, sup- 



PRINCIPAL ORES BEFORE THE BLOWPIPE 45 

pose a mineral was harder than 4, but 
softer than 5, and that it was nearer 5 
than 4, then we would call its hardness 4^. 

In order to preserve the scale some 
operators use a three-cornered file, first 
cutting the mineral and then the scale 
until a number is found, which is abraded 
to about the same depth as the mineral 
under examination. 

Since a set of minerals forming a scale 
of hardness is not always at hand, the 
following scale given by Chapman is 
appended : 

1. Yields easily to the nail. 

2. Yields with difficulty to the nail or 
just receives an impression from it. Does 
not scratch a copper coin. 

3. Scratches a copper coin but is also 
scratched by it, being of about the same 
degree of hardness. 



46 BLOWPIPE ANALYSIS 

4. Not scratched by a copper coin. Does 
not scratch glass. 

5. Scratches glass with difficulty, leaving 
its powder on it. Yields readily to the knife. 

6. Scratches glass easily. Yields with 
difficulty to the knife. 

7. Does not yield to the knife. Yields 
to the edge of a file, though with difficulty. 

8. 9, 10. Harder than flint. 

Specific gravity cannot well be deter- 
mined without the aid of a balance, and 
hence its value here is not great. 

As in the preceding chapter, alphabetic 
arrangement will be employed. 

ORES OF ANTIMONY 

Stibnite, Sb 2 S 3 , Sb.;i, S.2 9 . *H = 2, 
= 4.524.62. Of lead-gray color and 
metallic lustre. Consists of a large number 

* H = Hardness, G = Specific Gravity. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 47 

of needle-shaped crystals. Brittle. Fuses 
in candle flame. In an ignition tube yields 
a sublimate of sulphur. On Ch. before the 
Bp. it is volatilized, giving antimony coating 
and tinges the flame pale blue. 

ORES OF ARSENIC 

Native Arsenic, As. This contains traces 
of Sb, Ag, Fe, Co, and Ni. 

H = 3-5> = 5.7-5.8. Dark gray in 
color. Fracture tin-white, tarnishing rap- 
idly. Volatilizes before the Bp. on Ch. 
without melting, giving white coating of 
arsenious acid and characteristic garlic odor. 
In ignition tube it sublimes, giving arsenical 
ring. 

Realgar, AsS, As . 70, S . 30. H = 1.5 2, 
= 3.56. Bright red to orange-red color 
and resinous lustre. In an ignition tube 
it fuses and finally sublimes. The sub- 



48 BLOWPIPE ANALYSIS 

limate when cool is red and transparent. 
Fuses readily before the Bp. on Ch. and 
burns with - pale yellowish flame, emitting 
gray-white fumes having garlic odor. 

Orpiment, As 2 S 3 , As . 61, S . 39. 
H = 1.5 -2.0, 0=3.4-3.5. 

Lemon-yellow in color and resinous or 
pearly lustre. Sectile. Before the Bp. on 
Ch. behaves like realgar, but in an ignition 
tube it gives a dark yellow sublimate which 
is transparent. 

ORES OF BISMUTH 

Native Bismuth, Bi. This contains traces 
of As, Te, and S. 

H = 2.0 - 2.5, G = 9.7 - 9.83. Color, silver- 
white, slightly tinged with red. Metallic 
lustre. Brittle when cold, but may be lami- 
nated when hot. Before the Bp. on Ch. 
behaves like pure Bi. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 49 

Bismuthite, Bi 2 O 3 . 90, CO 2 . 7, H 2 O . 3, 
H = 4.0 -4.5, = 6.9-7.8. 

Usually of a white or light greenish color 
and vitreous lustre, in acicular crystalliza- 
tions. In an ignition tube decrepitates, 
yielding water and turning gray. Before 
the Bp. on Ch. it fuses easily and is reduced 
to metallic globule, coating the Ch. with 
Bi 2 O 3 . With Na 2 CO 3 it occasionally gives 
the sulphur reaction. 

ORES OF CHROMIUM 

Chromic Iron Ore, FeO.32, Cr 2 O 8 .68. 
A1 2 O 3 , Fe 2 O 3 , MnO, and MgO are commonly 
present. H = 5.5, = 4.32-4.57. Occurs 
usually massive. Color, iron-black to brown- 
ish black. In many varieties strongly mag- 
netic. Lustre, shining and somewhat me- 
tallic. Heated in an ignition tube, remains 
unchanged. Infusible before the Bp. on Ch. 



50 BLOWPIPE ANALYSIS 

Before the Bp. on Ch. with Na 2 CO 3 and 
KCN yields metallic iron. In borax bead 
it slowly dissolves to a clear transparent 
glass, which is a beautiful green when cool. 

ORES OF COBALT 

Smaltite, Co(Fe, Ni) As 2 , Co . 28, As . 72. 
H = 5.5, G = 6.37 - 7.30. Color, tin-white 
or steel-gray. Lustre, metallic. When 
heated to redness in an ignition tube it 
yields a sublimate of metallic arsenic. Before 
the Bp. on Ch. it fuses readily, with emis- 
sion of arsenical fumes, to a grayish black 
magnetic globule. This globule may be 
examined for iron, cobalt, and nickel with 
the borax bead. 

Cobaltite, CoS 2 + Co As 2 , Co. 36, As. 45, 
8.19. H = 5.5, = 6.0-6.3. Color, silver- 
white tinged with red. Metallic lustre. 
Before the Bp. on Ch. fuses easily, with 



PRINCIPAL ORES BEFORE THE BLOWPIPE 5 1 

emission of copious arsenical fumes, to a 
gray magnetic globule. Remains unchanged 
in the ignition tube. 

Linnaeite, (Co, Ni) 3 S 4 , (Co, Ni)s8, 8.42. 
H = 55, = 4.8-5.0. Color, bright steel- 
gray, sometimes reddish. Lustre, metallic. 
Crystallizes in the regular octahedron. 
Before the Bp. on Ch. fuses to a metallic 
globule which is attracted by the magnet. 
With borax bead gives reaction for cobalt. 

Erythrite, Co 3 O 8 As 2 + 8 H 2 O, 
CoO.37.6, H 2 O.24.o. 

H= 1.5 -2.0, 0=2.95. 

Color, crimson to peach-red. When crys- 
tallized, of pearly lustre, but frequently dull 
and earthy. Heated in ignition tube gives 
off water, and color changes to blue or 
green. Before the Bp. on Ch. in R. F. it 



52 BLOWPIPE ANALYSIS 

emits arsenical fumes and melts to a dark 
gray globule which with the borax bead 
reacts for cobalt. 

ORES OF COPPER 
Native Copper, Cu. 

H = 2.5- 3 , = 8.5-8.9. 

Color, copper-red. Lustre, metallic. Oc- 
curs usually massive and very arborescent. 
Before the Bp. on Ch. it fuses, and if 
the heat is sufficiently high it assumes a 
bright bluish-green surface ; on cooling it 
is covered with a coat of black oxide. In 
the borax bead it reacts for copper. 

Chalcopyrite, CuFeS 2 , Cu . 35, Fe . 30, 
8.35. H = 3.5 -4, = 4.1-4.3. Color, 
brass-yellow, often golden-yellow. Lustre, 
metallic. Occurs crystallized, but is gener- 
ally found massive. Is easily scratched 



PRINCIPAL ORES BEFORE THE BLOWPIPE 53 

with a knife. Heated in an ignition tube 
decrepitates, and occasionally yields a faint 
sublimate of sulphur. Before the Bp. on 
Ch. it blackens, but becomes red again on 
cooling. Before the Bp. on Ch. with Na 2 CO 3 
and KCN it is reduced, and the metals are 
obtained in separate masses. It reacts with 
the borax bead for copper and iron. 

Copper Glance, Cu 2 S, Cu .80, S . 20. 
H = 2.5 - 3.0, G = 5.5 - 5.8. Color, dark 
blue to steel-gray. Occurs in compact 
masses, often very shining. Before the Bp. 
on Ch. fuses to a globule which boils 
and emits glowing drops. Sulphur dioxide 
escapes abundantly, and the outer flame is 
colored blue. Before the Bp. on Ch. with 
Na 2 CO 3 yielding a metallic globule. 

Tetrahedrite, 4 CuS + Sb 2 S 3 . Frequently 
contains silver, iron, mercury, and zinc. 



54 BLOWPIPE ANALYSIS 

H = 3.0 -4.0, = 4.5-5. Color, steel-gray 
to iron-black. Heated in an ignition tube 
fuses and gives a sublimate of antimonious 
oxide. When mercury is present this con- 
denses in the upper part of the tube, form- 
ing the characteristic mirror. Before the 
Bp. on Ch. it fuses readily to a metallic 
globule, emitting dense white fumes ; zinc 
and antimony coatings are deposited on the 
Ch. After long ignition before the Bp., if 
the mineral is finely powdered and mixed 
with Na 2 CO 3 and KCN, the ore is reduced 
to the metal. 

Cuprite, Cu 2 O, Cu . 89, . 1 1. 
H = 3.5 -4.0, = 5.5-6.15. 

Color, intense crimson-red. Before the Bp. 
on Ch. blackens and fuses quietly, and finally 
yields a metallic globule of copper. Before 
the Bp. on Ch. with Na 2 CO 3 and KCN it 
is easily reduced. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 55 

Malachite, 2 CuO + CO 2 + H 2 O, CuO . 72, 
CO 2 .20, H 2 O.8. 

H = 3.5 -4.0, 0=3.90-4.03. 

Color, bright green. Occurs generally in 
mammillated concretions. Lustre, shining 
and fracture, silky. Heated in an ignition 
tube yields water and blackens. Before the 
Bp. on Ch. it fuses to a metallic globule. 
Before the Bp. on Ch. with Na 2 CO 3 and 
KCN it is easily reduced. With borax 
bead gives characteristic coloration. 

Azurite, 3 CuO + 2 CO 2 + H 2 O, CuO . 69, 
C0 2 .26, H 2 0. 5 . 

H = 3.5 -4.0, 0=3.77-3.83. 

Color, azure-blue. Occurs usually in crys- 
tallized or globular masses. Lustre, earthy 
or vitreous. Before the Bp. and with other 
reagents behaves like malachite. 



56 BLOWPIPE ANALYSIS 

Chrysocolla CuO + SiO 2 + 2 H 2 O, 
CuO.45.3, H 2 O.20.5. H = 2.0- 3.0, G=2. 
Color, bluish-green, closely resembling mala- 
chite. Occurs usually as an incrustation, 
its surface being very smooth, like enamel. 
In an ignition tube it blackens and yields 
water. Before the Bp. on Ch. in O. F. it 
blackens, coloring the flame bright green; 
in the R. F. it turns red. Before the Bp. 
on Ch. with Na-jCO 3 yields metallic copper. 
In borax bead it reacts for copper. 

Atacamite, CuCl 2 + 3 CuO 2 H 2 - Cl . 16.6, 
. 20.3, Cu . 50. i , H 2 O . 1 3.0. 

H = 3.0 -3.5, G= 3.75 -3.77. 

Color, green to blackish green. Lustre, 
adamantine to vitreous. In an ignition 
tube yields water. Before the Bp. on Ch. 
colors flame blue. Before the Bp. on Ch. 
with Na 2 CO 3 and KCN is reduced to the 
metal. In borax bead it reacts for copper. 



PRINCIPAL ORES BEFORE THE BLOWPIPE S7 

ORES OF IRON 

Limonite, 2 Fe 2 O 3 + 3 H 2 O, Fe 2 O 8 . 86, 
H 2 O . 14. H = 5.0-5.5, G = 3.6 - 4.0. 
Color, brown to ochre-yellow. Earthy or 
semi-metallic in appearance. In an igni- 
tion tube yields water. Before the Bp. 
on Ch. infusible. In borax bead reacts for 
iron. 

Hematite, Fe,O 3 , Fe . 70, . 30. 
H = 5-5 -6-5, = 4.9-5.3. 

Color, dark steel-gray to iron-black. Lustre, 
metallic. When pulverized yields a red 
powder. Before the Bp. on Ch. infusible. 
After long roasting becomes magnetic. In 
borax bead gives usual indications of iron. 

Magnetite, Fe 3 O 4 , FeO .31, Fe 2 O 3 . 69. 
H = 5-5 -6.5, 0=5.17-5.18. 



58 BLOWPIPE ANALYSIS 

Color, iron-black. Lustre, shining and me- 
tallic. Pulverized, its powder is black. It 
is strongly magnetic. Fuses with difficulty 
before the Bp. on Ch. In borax bead reacts 
for iron. 

Pyrites, FeS 2 , Fe . 47, S . 53. 

H = 6.0 - 6.5, G = 4.95 - 5.20. 
Color, brass-yellow. Lustre, metallic. Oc- 
curs commonly in cubes. It often con- 
tains small quantities of Au, Ag, Cu, As, 
Co, and Mn. Heated in an ignition tube 
gives a sublimate of sulphur, the residue 
becoming magnetic. Before the Bp. on 
Ch. in O. F. sulphur is burned off and 
the red oxide remains. This residue may 
then be examined for iron, etc. 

Marcasite (White Iron Pyrites). Having 
the same general composition as pyrite, but 
much lighter in color. Crystals, prismatic. 
Before the Bp. on Ch. behaves like pyrite. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 59 

Pyrrhotite, Fe 7 S 8 , Fe.6o.5, 8.39.5. 
H = 3.5 -4.5, = 4.58-4.64. 

Color, bronze-yellow. Closely resembles 
pyrite, but may be distinguished from it 
by being feebly magnetic. Heated in an 
ignition tube yields no sublimate. Before 
the Bp. on Ch. fuses to a magnetic globule, 
which exhibits a yellowish crystalline struc- 
ture when fractured. 

Mispickel, FeAsS, Fe.34, As. 46, 8.20. 
H = 5.5~6.o, G = 6.0 -6.2. Color, silver- 
white. Lustre, metallic; very brittle. Often 
associated with it we find small quantities 
of Co, Ag, and Au. Heated in an igni- 
tion tube it first yields a red sublimate of 
sulphide of arsenic, and then afterward 
a crystalline sublimate of metallic arsenic. 
Before the Bp. on Ch. emits dense fumes 
of arsenic and deposits a coating on the 



60 BLOWPIPE ANALYSIS 

coal; it then fuses to a globule which 
behaves like pyrrhotite. 

Siderite, FeCO 3 , FeO.6 2 , CO 2 .38. 
H = 3.5 -4.5, 0=3.7-3.9. Color, grayish 
yellow to reddish brown. Lustre, pearly. 
Crystallizes in rhombohedrons with curved 
faces ; these crystals are distinctly cleavable 
and massive. Heated in an ignition tube 
it decrepitates with evolution of carbon 
dioxide. Before the Bp. on Ch. infusible. 
Before the Bp. on Ch. with Na 2 CO 3 it fuses 
to a magnetic mass. With borax bead it re- 
acts for iron and sometimes for manganese. 

ORES OF LEAD 
Galena, PbS, Pb . 87, S . 1 3. 
H = 2.5, 0=7.4-7.6. 

Color, bluish gray, slowly tarnishing. Lus- 
tre, metallic. Crystals in the form of cubes. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 6 1 

Heated in an ignition tube it sometimes 
decrepitates and yields a sublimate of sul- 
phur. Before the Bp. on Ch. easily reduced 
to the metallic state, the Ch. becoming 
coated with sulphate and oxide of lead. 
The metallic globule usually contains a 
little silver. To separate this, the process 
known as "cupellation" is employed. A hole 
is bored into the Ch. about i cm. in diame- 
ter and about 6 mm. deep. Into this hole 
is placed a stiff paste made by mixing finely 
pulverized bone-ash with a little soda and 
water. This paste is pressed in hard, and 
then the surface is smoothed off, and the 
centre is slightly depressed with the rounded 
end of a glass rod. The charcoal so pre- 
pared is set in a warm place to allow the 
paste to dry. When the paste is quite 
dry the small globule of lead is placed in 
the depression in the centre of the bone- 
ash "cupel," and is there exposed to the 



62 BLOWPIPE ANALYSIS 

O. F. from the Bp. The lead is oxidized 
and is absorbed by the bone-ash, while any 
silver present will remain in the central 
depression as a bright shining bead. 

Cerusite, PbCO 3 , PbO . 84, CO 2 .i6. 
H = 3.0 -3.5, = 6.46-6.57. Color, white, 
gray, or yellow. Lustre, adamantine. Crys- 
tallizes in prismatic needles When heated 
in an ignition tube carbon dioxide is evolved 
and the residue turns yellow. Before the 
Bp. on Ch. readily reduced to metallic 
lead. 

Anglesite, PbSO 4 , PbO . 74, SO 3 .26. 
H = 2.03.0, = 6.12 6.39. Color, yel- 
low, gray, and brown. Lustre, adamantine, 
resinous. Heated in an ignition tube 
decrepitates, and sometimes yields a little 
water. Before the Bp. on Ch. fuses to 
a clear bead, which on cooling becomes 



PRINCIPAL ORES BEFORE THE BLOWPIPE 63 

opaque. Before the Bp. on Ch. with 
Na 2 CO 3 is reduced to the metal giving a 
yellow coating. The Na^Og absorbed by 
the coal reacts for S. 

ORES OF MANGANESE 

Pyrolusite, MnO 2 , Mn . 63.2, O . 36.8. 
H = 2.02.5, = 4.82. Color, iron-black to 
steel-gray. Lustre, non-metallic. Heated 
in an ignition tube yields generally a little 
water, and if the temperature be high 
enough, oxygen is evolved. Before the 
Bp. on Ch. infusible. In borax bead gives 
characteristic color. 

Psilomelane, Mn 2 O 8 + H 2 O. 

H = 5.5 -6.0, 0=3.7-4.7. 

Color, iron-black to steel-gray. Generally 
resembles pyrolusite, but is distinguished 
from it by its superior hardness. It fre- 



64 BLOWPIPE ANALYSIS 

quently contains BaO and Li 2 O. It behaves 
before the Bp. like pyrolusite. 

Wad (Bog Manganese). This mineral is 
essentially MnO 2 , MnO, and H 2 O, with 
small quantities of Fe 2 O 3 , A1 2 O 3 , BaO, SiO 2 , 
etc., associated with it. 

H = 0.5 -6.0, = 3.0-4.2. Color, dull 
black. Heated in an ignition tube yields 
water in abundance, otherwise it behaves 
like pyrolusite. 

ORES OF MERCURY 

Native Mercury, Hg. G = 13.5 13.6. 
Color, silver-white. Is liquid at all ordi- 
nary temperatures. Heated in an ignition 
tube is volatilized, the vapors condensing 
in the upper end of tube to small metallic 
globules of Hg. Before the Bp. on Ch. it 
is volatilized. Frequently contains Ag. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 65 

Cinnabar, HgS 2 , Hg.86, S. 14. 
H = 2.0 -2.5, G = 8.0 -8.2. 

Color, scarlet-red to brick-red. Lustre, non- 
metallic. When pulverized yields a powder 
of vermilion-red color. Heated in an ig- 
nition tube it volatilizes, yielding a black 
sublimate, which by friction becomes red. 
Before the Bp. on Ch. it is wholly vola- 
tilized. Heated in an ignition tube with 
Na 2 CO 3 metallic mercury sublimes, con- 
densing in the upper portion of the tube 
in minute globules. 

ORES OF NICKEL 

Millerite, NiS, Ni.644, $.35.6. 
H = 3.0 -3.5, 0=5.2-5.6. 

Color, brass-yellow. Brittle. Before the 
Bp. on Ch. it fuses to a magnetic, metallic 
globule. The roasted mineral gives in the 
borax bead the color reaction characteristic 



66 BLOWPIPE ANALYSIS 

of nickel, and sometimes that of cobalt, 
which is often associated with it. 

Niccolite, NiAs, Ni . 44, As . 56. 
H = 5.0 -5.5, G= 7.35 -7.67. 

Color, pale copper-red. Lustre, metallic. 
Very brittle. Heated in an ignition tube 
yields a copious sublimate of arsenious 
oxide, the residue falling to a greenish 
powder. Before the Bp. on Ch. fuses to a 
white brittle globule emitting arsenical 
fumes. In borax bead gives color character- 
istic of nickel. Frequently in this mineral 
a portion of the arsenic is replaced by 
antimony. 

ORES OF SILVER 
Native Silver, Ag. 

H = 2.5 3.0, G=IO.I n.o. 
Color, silver-white. Lustre, metallic. Duc- 
tile and malleable. Usually occurs asso- 



PRINCIPAL ORES BEFORE THE BLOWPIPE 6/ 

ciated with Au, As, Sb, Cu, Fe, etc. 
Before the Bp. on Ch. easily fuses to a 
globule which is surrounded with a dark 
red coating on the coal. 

^ 

Argentite, Ag. 2 S, Ag.S/.i, S. 12.9. 
H = 2.0 2.5, 0=7.20-7.36. 

Color, blackish lead-gray. Lustre, metallic. 
Very sectile. Before the Bp. on Ch. in 
O. F. intumesces with evolution of sulphur 
dioxide, finally yielding a metallic globule 
of Ag. 

Pyrargyrite, Ag 3 SbS 3 , Ag.59.8, Sb.22.5, 
8.17.7. H = 2.5, 0=5.77-5.86. Color, 
black to dark cochineal-red. Lustre, metal- 
lic, adamantine. In an ignition tube it 
yields on continued heating a sublimate of 
antimony sulphide. Before the Bp. on Ch. 
it gives a coating of antimony trioxide. 



68 BLOWPIPE ANALYSIS 

Before the Bp. on Ch. with Na 2 CO 3 is 
reduced to metallic silver. 

Proustite, Ag 3 S 3 As, Ag.65.5, As. 15.1, 
S. 194. H = 2.0 -2.5, 0=5.57-5.64. 
Color, light red. Lustre, splendent, adaman- 
tine. Before the Bp. on Ch. it behaves like 
pyrargyrite, save that it gives off arsenical 
fumes instead of antimonious oxide. 

Stephanite, Ag 5 S 4 Sb, Ag.68.5, Sb.is.3, 
S . 16.2. H = 2.0 2.5, G = 6.2 6.3. Color, 
iron-black to blackish gray. Lustre, me- 
tallic. Very brittle and fragile. In an ig- 
nition tube it decrepitates, fuses, and finally 
yields a slight sublimate of antimony tri- 
sulphide. Before the Bp. on Ch. gives a 
coating of antimonious oxide. Before the 
Bp. on Ch. with Na 2 CO 3 a globule of 
metallic silver is obtained. The mineral 
frequently contains copper and iron. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 69 

Kerargyrite, AgCl, Ag.753, 0.24.7. 
H =1.01.5, 0=5.52. Color, white, gray, 
yellowish, greenish to blue. Lustre, resin- 
ous, adamantine. Soft like wax. Fuses 
easily in a candle-flame. Before the Bp. 
on Ch. it is readily reduced to metallic 
silver. 

ORES OF TIN 

Cassiterite, SnO 2 , Sn.79, O.2i. 
H = 6.0 -7.0, = 6.8-7.0. 

Color, brown, black. Lustre, adamantine, 
brilliant. Occurs crystallized in square 
prisms. Reentrant angles characteristic. 
Before the Bp. on Ch. with Na 2 CO 3 and 
KCN reduced to a metallic globule of tin. 
In the borax bead gives characteristic re- 
action. 

Stannite, 2 Cu 2 S . SnS 2 + 2 (FeS . ZnS) 
Sn . S 2 . H = 4.0, G = 4.3 4.5. Color, 



70 BLOWPIPE ANALYSIS 

steel-gray to iron-black. Lustre, metallic. 
Occurs usually massive and disseminated. 
Heated in an ignition tube it yields sul- 
phur dioxide. Before the Bp. on Ch. it 
emits sulphur dioxide and becomes cov- 
ered with oxide of tin. Before the Bp. on 
Ch. with Na 2 CO 3 and KCN it gives an 
impure globule of copper. A very difficult 
mineral to determine. 

ORES OF ZINC 

Calamine, H 2 Zn 2 O 5 Si, SiO 2 .25.o, ZnO. 
67.5, H 2 O.7.5. H = 4.5 -5.0, 0=34-3.5. 
Color, white, gray, bluish, or brown. Lustre, 
vitreous. Brittle. In an ignition tube 
yields water when heated and becomes 
milky white. Before the Bp. on Ch. prac- 
tically infusible. With Co(NO 3 ) 2 it assumes 
a green color which passes into a fine blue 
when the heat is increased. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 71 

Smithsonite, 

Zn . CO 3 , ZnO . 64.8, CO 2 . 35.2. 

H = 5, = 4.30-445. Color, gray, yellow, 
brown, and green. Lustre, vitreous, pearly. 
Heated in an ignition tube CO 2 is evolved, 
residue appearing white. It often contains 
impurities of Cd, Pb, Fe, Mn, Ca, and Mg. 
When these are present the residue in the 
ignition tube becomes dark on cooling. 
Before the Bp. on Ch. with Na 2 CO 3 and 
exposed to the R. F. it is decomposed. It 
gives the characteristic reaction for zinc 
with Co(NO 3 ) 2 . 

Zincite, ZnO, Zn . 80.3, . 19.7. 
H = 4.0 -4.5, = 5.43-5.70. 

Color, blood-red. Lustre, brilliant, sub- 
adamantine. Before the Bp. on Ch. infusible. 
Before the Bp. on Ch. with Na 2 CO 3 gives 
coating of zinc oxide. Oives characteristic 



72 BLOWPIPE ANALYSIS 

reaction with Co(NO 3 ) 2 . It frequently con- 
tains a small quantity of Mn 2 O 3 , which may 
be detected in the borax bead. 

Sphalerite, ZnS, Zn . 67, S . 33. 
H = 3-5-4-0, 0=3.9-4.1. 

Color, yellow to black. Lustre, resinous, brill- 
iant, and sometimes submetallic. Heated 
in an ignition tube sometimes decrepitates. 
Before the Bp. on Ch. infusible. Before the 
Bp. on Ch. with Na 2 CO 3 easily reduced. 
With Co(NO 8 ) 2 gives the characteristic re- 
action. It frequently contains small quan- 
tities of Cd, Hg, Sn, Pb, Au, Ag, etc. 



PRINCIPAL ORES BEFORE THE BLOWPIPE 73 



TABLE OF COLORS OF COATINGS ON CHARCOAL 



ELEMENT 


COLOR HOT 


COLOR COLD 


Antimony 
Arsenic 
Bismuth 
Cadmium 


(Rather volatile) 
(Very volatile) 
Orange-Yellow 
Brownish Yellow 


White 
White 
Lemon-Yellow 
Reddish Brown 


Lead 
Silver 


Lemon- Yellow (volatile) 
Dark Red 


Lemon-Yellow 
Dark Red 


Tin 


Faint Yellow 


White 


Zinc 


Yellow 


White 



II 



TABLE OF FLAME COLORATIONS 



RED 


YELLOW 


GREEN 


Calcium 


Sodium 


Barium 


Lithium 




Boron 


Strontium 




Iodine 


BLUISH GREEN 


BLUE 


VIOLET 


Bromine 


Chlorine 


Potassium 


Copper 






Phosphorus 







74 



BLOWPIPE ANALYSIS 



III 



TABLE OF COLORS OF BORAX BEADS IN OXIDIZING FLAME 



ELEMENT 


COLOR HOT 


COLOR COLD 


Aluminum 


Colorless to Cloudy 


Colorless to Cloudy 


Antimony 


Yellowish 


Colorless 


Barium 


Colorless to Opaque 


Colorless to Opaque 


Bismuth 


Yellow 


Colorless 


Cadmium 


Yellow 


Colorless to White 


Calcium 


Colorless 


Colorless 


Chromium 


Reddish Yellow 


Yellowish Green 


Cobalt 


Blue 


Blue 


Copper 


Green 


Greenish Blue 


Iron 


Orange 


Yellow 


Lead 


Yellow 


Colorless 


Magnesium 


Colorless 


Colorless 


Manganese 


Violet 


Reddish Violet 


Nickel 


Violet 


Reddish Brown 


Silver 


Colorless 


Milk-White 


Strontium 


Colorless to Opaque 


Colorless to Opaque 


Tin 


Colorless 


Colorless 


Zinc 


Yellowish 


Colorless 



PRINCIPAL ORES BEFORE THE BLOWPIPE ?$ 



IV 



TABLE OF COLORS OF BORAX BEADS IN REDUCING FLAME 



ELEMENT 


COLOR HOT 


COLOR COLD 


Aluminum 


Colorless 


Colorless 


Antimony 


Colorless 


Cloudy 


Barium 


Colorless 


Colorless 


Bismuth 


Colorless 


Gray Cloudy 


Cadmium 


Colorless 


Gray Cloudy 


Calcium 


Colorless 


Colorless 


Chromium 


Green 


Green 


Cobalt 


Blue 


Blue 


Copper 


Colorless 


Red 


Iron 


Yellowish Green 


Yellowish Green 


Lead 


Colorless 


Gray 


Magnesium 


Colorless 


Colorless 


Manganese 


Colorless 


Pink 


Nickel 


Colorless 


Gray Cloudy 


Silver 


Colorless 


Gray 


Strontium 


Colorless 


Colorless 


Tin 


Colorless 


Colorless 


Zinc 


Colorless 


Gray 



BLOWPIPE ANALYSIS 



TABLE OF COLORS OF MICROCOSMIC SALT BEADS IN 
OXIDIZING FLAME 



ELEMENT 


COLOR HOT 


COLOR COLD 


Aluminum 


Colorless 


Colorless 


Antimony 


Yellowish 


Colorless 


Barium 


Colorless to Opaque 


Colorless to Opaque 


Bismuth 


Yellow 


Colorless 


Cadmium 


Yellowish 


Colorless 


Calcium 


Colorless 


Colorless to Opaque 


Chromium 


Reddish 


Green 


Cobalt 


Blue 


Blue 


Copper 


Green 


Greenish Blue 


Iron 


Red 


Brownish Red 


Lead 


Yellowish 


Colorless 


Magnesium 


Colorless 


Colorless 


Manganese 


Brownish Violet 


Reddish Violet 


Nickel 


Reddish 


Yellow 


Silver 


Yellowish 


Yellowish 


Strontium 


Colorless 


Colorless 


Tin 


Colorless 


Colorless 


Zinc 


Yellowish 


Colorless 



PRINCIPAL ORES BEFORE THE BLOWPIPE 77 



VI 

TABLE OF COLORS OF MICROCOSMIC SALT BEADS IN 
REDUCING FLAME 



ELEMENT 


COLOR HOT 


COLOR COLD 


Aluminum 


Colorless 


Colorless 


Antimony 


Colorless 


Gray Cloudy 


Barium 


Colorless 


Colorless 


Bismuth 


Colorless 


Gray Cloudy 


Cadmium 


Colorless 


Gray Cloudy 


Calcium 


Colorless 


Colorless 


Chromium 


Reddish 


Green 


Cobalt 


Blue 


Blue 


Copper 


Dark Green 


Brownish Red 


Iron 


Red 


Reddish 


Lead 


Colorless 


Gray Opaque 


Magnesium 


Colorless 


Colorless 


Manganese 


Colorless 


Colorless 


Nickel 


Colorless 


Gray 


Silver 


Colorless 


Gray 


Strontium 


Colorless 


Colorless 


Tin 


Colorless 


Colorless 


Zinc 


Colorless 


Gray Cloudy 



THE PRACTICAL METHODS 

OF 

ORGANIC CHEMISTRY 

AUTHORIZED TRANSLATION 
1 2 mo. Cloth. Price, $1.60, net 

BY TRANSLATED BY 

LUDWIG GATTERMANN, Ph.D., WILLIAM SHAFER, Ph.D., 

Professor in University of Heidelberg. Instructor in Organic Chemistry 

in Lehigh University. 



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