Helena weekly herald. [volume] (Helena, Mont.) 1867-1900, 1884-04-10

dlSeuUlleTOuS Salena." 1nlS mineral d.
ways has more or less silver, wherever
found, but the amount of silver is so small
that the per cent is rarely ever given; the
silver being spoken Of as going so many
ounces to the ton.
In the vein at Comet City the galena
varies greatly in the amount Of silver con-
tained, some of the coarse cubical specimens
giving from 3 to Z ounces to the ton, while
the fine granular specimens often give sew
eral hundred ounces to the ton.
1t is remarked that the small galena
grains or cubes which have rounded cor
ners are almost sure to contain the most
silver. Silver found in galena is combined
with sulphur and forms argentite, or silver
glance, but in so finely divided state as
to be rarely noticed. Very many of Mon
tana's leading mines are really lead mines,
which contain silver in remarkable quanti-
ties. beside the product of the lead itself.
Cerussite-This is the carbonate of lead,
which occurs abundantIy at Leadville,
Col, and at Lion Mountain, in this Terri
tory. 1t is produced by the decomposition
of galena, the sulphurs of that mineral
being replaced by carbOnic acid, derived
usually from neighboring limestone rocks
This mineral is found quite extensively
ditfused in the decomposed honey-combed
| quartz of the upper levels of the mines
upon the Comet lode. Various shades of
color are given to the quartz, as green, yel-
low and gray.
The carbOnates in the vein are richer in
silver than the galeDa, showing that the
weathering has concentrated the silver.
This mineral is, however, limited to the
surface ores and does not figure much in
the output of the mines.
Leadhillite-A mineral of sulphate and
carbonate of lead occurs with the above
mineral in small quantities, and is consid-
cred merely variety and not a separate
species of mineral. 1t is produced by the
decomposition of the sulphides.
IRON ORES AND MINERALS
Pyrite-IrOn sulphide: 1t is composed
essentially of AZ per cent. of iron and SO
per cent of sulphur, and is one of the most
common minerals on the globe. 1t occurs
in large cube crystals of brassy-yellow
color, and is found in all the lower work
ings of the mines upon this lead, below
the action of the atmos phere.
Marcasite-This is another iron sulphide
differing but little in composition from the
former, but is of a white color and in pris-
matte crystals. 1t is quite liable to de-
compose when exposed to the atmosphere.
ArsenOpyrite, or mispickel, is composed
of iron united with both sulphur and
arsenic, and is termed "arsenical iron pyri-
tes" Its color silver white, and it is of
granular texture and uneven fracture.
This mineral may be readily detected
from the other sulphides of iron by the
strong arsenical garlic fumes given off
when heated upon charcoal before the
blOwpipe. 1t is found in the lower work
ings of the mines.
acknowledgements iron ore, is the ses-
quioxide of firon-iron combined with Oxy-
gen in the proportion of 20 parts of the
former to 80 parts of the latter. This is
the ordinary rusty looking iron ore so
common upon the surface of the outcrop-
ping ledges of mineral bearing veins.
Many varieties occur as red and yellow
Ochre, clay iron stone, etc.
Magnetite-the black oxide of iron. 1t
occurs as minute disseminated crystals in
the country granite enclosing the quartz
vein, and may be recognized in its strong
attraction for the magnet.
Limanite-The oxide of iron combined
chemically with water, and is called hy-
drafted iron oxide. 1t is usually of a brown
color and occurs near the surface.
Melanterite- or iron vitriol is
sulphate of iron and occurs as yellOwish |
powder upon the dump piles of pyrite-
bearing rocks, and results from the action |
Of the water upon the iron pyrites.
COPPER BEARING ORES AND MIREALs.
Native copper occurs sparingly distribu- |
ted in the seams where water percolates
the ledge of ore The former copper sui |
phide evidently lost it's sulphur and be-
came an oxide, and this, being deoxidized
by action of water possessing reducing |
qualities, has left the pure copper.
CalcOpyrite-A mixture of iron and cop
per sulphides, commonly called copper py
rites Not very abundant.
Malachite.-The green copper carbonate.
1t occurs as an incrustatiOn upon the ore
bearing quartz.
Azmite-The blue copper carbonate
Occurs with the former mineral in incrus-
tatiOn.
MANGANESE ORES AND MINERALS.
PsilOmelane. - Occurs massive, color
black. Is an oxide of manganese. 1t
occurs in upper levels.
Wad. or bog manganese Occurs with the
former mineral, also coating other rocks
|
or brownish black, and has the property of
sOiling the fingers. 1t is more or less COM
bined chemically with water, forming a
hydrated manganese ore. Manganese ores
may be identified by their property of
forming violet colored glass when fused
with borax before the blowpipe upon char
coal.
ZINC ORES AND MINERALS.
Sphalerite. blend, or "black jack''
of the miners. 1t is very abundant in the
upper levels of the mines. 1t is the sui
phide of zinc.
Smithsonite.-Thec carbonate of zinc-is
found associated with the former mineral
where the chemical change from sui
phide to a carbonate has been possible
Cadmium was also found associated with
this mineral in small quantities.
The following minerals were also identi-
fed:
Calcite.-The crystalline carbonate of
lime commonly called calc-spar.
Kaolinite- An illuminate of silica,
Of greasy feel. Of various colors, accord
ing to varying quantities of iron present.
MuscOvite.-Mica, an ingredient of gran
ite.
Orthoclase.-Common feldspar, also an
ingredient of granite.
Quartzi.e.-Common quartz; another in
gredient of granite |,
Tale, in the form of soapstone or steatite,
occurs as filling in many of the seams
and SLIPS of vein rock.
Amphibole, or hornblende. Resembles
mica, but is less elastic. M
One unaccustomed to examination of
mines will wonder at the number of min
erals, but it is more remarkable that an