Helena weekly herald. [volume] (Helena, Mont.) 1867-1900, 1884-04-10
POPULAR SCIENCE.
Minerals Ofa Montana Mine.

natural sciences first, afterwards those NOR
complex.
The inorganic world antedates the or
ganic the foundations of the earth had tC
be securely placed before the introduction
of organized forms.
Leaving the chemical structure of tn,
earth, for the time being, as rather techni
cal for the present article, and reservins
tor a more elaborate series of article, th,
consideration of the geological features O
our Territory, we will Immediately consider
some of the mineral features of Montana
as, at the present time, great interest i:
manifested in the mineral wealth.
Young investigators usually feel more
satisfaction in clearly defined individual
minerals than the more minute division
into chemical elements, or in their combi
nation into rocks.
Dana defines mineral as "The materials
of which the earth consists"
This definition will answer our purpose
if we distinctly bear in mind that minerals
are composed either of single, simple ele-
ment, as gold, silver, copper, etc, OF of a
combination of chemical elements, as
galena, pyrite, blende, feldsite, quartz, mica
water, etc.
Rocks, again, are composed of one
mineral, as limestone, quartzite, etc, to-
gether with existing impurities, or are
combinations, or mixtures of several miner
ais, variously distributed through the rock
mass, as granite, syenite gneiss, slate, etc.
Many minerals are sparingly scattered
through the body of our rocky envelope,
and the microscope may be made to reveal
them to the careful student, but to the
casual observer the clearly defined minerals
are of the most interest
Minerals are crystalline in structure,
some being found in large, beautiful forms,
while others are composed of minute crys-
tai grains whose polished faces reflect the
rays of the sun in interesting prismatic
colors, but their forms are too minute for
the eye to study unaided by the micro
scope.
This law of symetry of form in the
mineral world is universal in fact the
earth itself has a crystalline foundation
The granite mountains are composed of
crystals. The melted lava from volcanoes
cools, solidifies, and becomes a mass of
crystalline grains.
Water, that most common and widely
distributed of all minerals, has but to be
cooled to 30 degrees F. to assume charming
crystalline forms, as exhibited in snow,
hOar frost, ice, etc.
OCCURRENCE OF MINERALS.
The natural receptacles for minerals are
the cracks, veins, seams, assures, dykes
and cavities which occur in the rocky
strata forming our earths surface.
They are produced by various causes, as
shrinkage, foldings, breaks, faults, etc, of
the hardened crust of the earth.
Some of these breaks in the earth's crust
were filed with melted rock material from
below; these are termed dykes. Others
have been slowly filled by mineral matter
being deposited from waters highly charged
with minerals in solution; and others yet
by mineral vapOrs being condensed in
these natural receptacles.
Mature abhOrS vacuum" and all
these openings formed by various agencies
must be filed, if possible; hence we find
the fssure veins of our mountains some
times containing rich mineral wealth,
while in other localities we find the veins
filled with boulders, gravel, sand, quartz
n nd hrnl horr nf min frao
ures.
We study minerals as we do individuals
by various characteristics Each mineral
carries its individual features, whenever
produced and wherever found. Quartz is
known by it's individual characteristics
wherever it occurs, whether in Europe,
Asia, Africa America, or the isles of the
sea, and this is true of every prime miner
al with which we are acquainted.
The more common physical properties Of
minerals are, hardness, specific gravity, re-
fraction, color, lustre, taste, odor and mag
netic department.
In studying the minerals of any section
of country, it is best to select one promi-
nent po;nt, where minerals occur, and
make careful study of the locality and
the minerals associated in that formation.
This may be taken as a point with
which to compare other localities, as geol-
ogists use the New York section of geOlog-
ical formation as key with which to COM
pare other points.
During the summer of 1881, the writer
had an opportunity of collecting and study
ing the minerals found at Comet City, JEFF
ferson county, in this Territory. The OBJ
here recorded are presented for
the purpose of arousing an interest among
1t seems probable that one person at
least in each camp in the Territory might
be found who would make careful list of
the mineral species in his locality. or,
make collection of them and state where
and how they occurred.
The mother vein or mineral land at
Comet City occurs in granitic belt, and
runs nearly east and west. The gangue
rock is quartz, and in many places contains
masses of bouldes and wash material.
Several tale floors, or faults filled with tale,
occur, often causing the mineral bearing
quartz to disappear in q very provoking
to the miners.
There are several mines located upon
this mineral land, which, so far as pros
pected, show plenty of valuable ore.
The following list of minerals found at
this locality is, of course, imperfect, as con-
work has been done since the list
was made, and probably others have been
discovered:
LEAD ORES AND MINERALS.
Galenite: Galena, lead sulphide, the
great lead ore all over the world, composed
of 81 parts lead and 13 parts
sulphur. It occurs in large cubical crys-