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GEMS AND PRECIOUS STONES. 669
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Crystal
Peak, is held by Whitmore & Sanders, both members of the Crystal
Peak Gem Co. G. H. Weed, of the same company, holds a homestead claim
at the foot of Crystal Peak on the southeast side, on which, some
promising amazon stone was found in digging for water. The best amazon
stone was seen in place on the claim of J. D. Endi-cott, on the
northeast side of the gap between Little Crystal Peak and Deer
Mountain. In one prospect trench, about 40 feet long on this claim,
amazon stone is exposed along the footwall of a pegmatite vein striking
N. 20° E. with a dip 30° E. The crystals in this wall range from small
size to 4 or 5 inches thick, and the exteriors of some are
exceptionally bright bluish green. Good amazon stone has been found on
many other claims in the Crystal Peak region, but the exposures were
not sufficiently good to determine what prospects are the most
promising.
The
various workings for amazon stone and other minerals cover cinsiderable
ground, but none of them are deep. On some of the claims there are pits
every few feet over an area of an acre or more. Practically all of the
work has consisted of pits, small open cuts, and occasional tunnels.
Most of the workings are less than 12 feet deep, and many have become
partly filled with rubbish. In all probably 200 pits were seen, and
there are many more in the region that were not visited. The country
rock of the Crystal Peak region is chiefly coarse red-dish biotite
granite, more or less porphyritic in places. A finer-grained aplitic
granite was closely connected with the mineral deposits noted in some
of the prospects. Over most of the country the coarse granite has been
partly disintegrated and broken down to coarse angular gravelly soil.
An accumulation of leaf mold with this has furnished a soil covering
for part of the area, so that good outcrops are not abundant. In places
the granite outcrops in hard ledges, large bowlders, or gravelly soil
without much vegetation, so that that prospecting is easier. Many of
the deposits can be mined without blasting because of the
disintegrated nature of the granite and the gem-bearing rock, but some
of them have to be blasted almost from the outcrop down.
The
amazon stone and associated minerals occur in pocket-like deposits more
or less irregularly distributed through certain parts of the massive
coarse granite of the region. The pockets are miarolitic cavities lined
with coarse and often nearly perfectly crystallized microcline and
albite feldspar, smoky and colorless quartz, and biotite mica, with
occasional crystals of topaz, phenacite, fluorite, colum-bite, and
gothite. Deposits and stains of limonite are abundant. The layer of
coarsely crystallized minerals fining the pockets varies from a
fraction of an inch to more than a foot in thickness in some places.
These pocket linings are typical pegmatite aggregations, which may
grade into the surrounding granite or have rather sharp contacts with
it. Some of the contacts are plainly banded and the gradation from the
pegmatite to the granite is so gradual that it is difficult to
determine the actual contact. This is especially true where the pockets
are associated with aplitic granite. Some of the gem
p
ockets occur in streaks as in pegmatite veins, but others appear to bear no definite relation to one another.
Amazon
stone is widely distributed in the Crystal Peak region, but most of the
deposits yield but little material suitable for gem
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