Scientific American Supplement, No. 344, August 5, 1882Various
Science
Scientific American Supplement, No. 344, August 5, 1882
Various
Science -- Periodicals
_Apopholite_.--This beautiful mineral has been found in fair abundance
at times in Shafts No. 1 and 2 in pockets, and seldom in place, most of
it being taken from the loose stone at the mouth of the shaft, and it
may generally be found on the dump. It is readily mistaken for calcite
by the miners and those unskilled in mineralogy, but a drop of acid will
quickly show the difference. The sizes of the crystals are very various,
from an eighth of an inch long or thick, to, in one case, an inch and
a half. The colors have been varied from white to nearly all tints,
including pink, purple, blue, and green; the white variety is, however,
the most abundant, and makes a handsome cabinet specimen. The crystals
are generally packed together in a mass, but are frequently set apart as
heavy druses of crystals having the form shown in Fig. 7. Sometimes,
as in the former grouping, the crystals are without the pyramidal
terminations, and are then right square prisms. The fracture being at
perfect right angles, distinguishes it from calcite. Its hardness is
generally fully 5, the specific gravity between 2.4 and 2.5; it is
difficult to fuse before the blowpipe, but is finally fused into an
opaque globule. Upon heating with nitric acid it partly dissolves, and
the remainder becomes flaky and gelatinous. Apopholite, although quite
rare, now may be bought from the men, or at least one of the engineers
of Shaft No. 2's elevator, and generally at low terms.
_Phrenite_.--This mineral is quite abundant in Shafts No. 1 and 2, in
very small masses, incrustations, and even in small crystals. It
occurs embedded in or incrusting the trap, and also with calcite and
apopholite. The only sure place to find it is at the southwest side of
an opening through the pile of drift rock under the trestle work of the
tramway, between shaft No. 1 and the dump, and within a few feet of a
number of wooden vats sunk into the ground seen just before descending
the hills and near the edge. Here on a number of blocks of trap it may
be found, a greenish white incrustation about as thick as a knife blade;
it also may be found on the main dump, and is sometimes found in plates
one-eighth of an inch thick, of a darker green color, upon calcite. Its
easiest distinguishment from the other minerals of this locality, with
which it might be confounded, is its great hardness of from 6 to 7.
It is very fragile and brittle, however, and is never perfectly
transparent, but quite opaque; its specific gravity is 2.9, and it is
readily fused before the blowpipe after intumescing. It partly dissolves
in acid without gelatinizing, leaving a flaky residue; it is a beautiful
mineral when in masses or crystals of a dark green color, but the best
place in the vicinity to secure specimens of this kind is, as I will
detail hereafter, at Paterson, N. J.
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