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PRECIOUS STONES.
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neighborhood of San Francisco, though not of fine quality; some of this stone has been used in building and for sidewalks.
Fine
red jasper is found on the Little Colorado river, New Mexico, and also
on the Willamette, Oregon. The latter region evidently furnished the
material for the fine arrow points of Oregon.
The
banded jasper found near Colyer, Graham county, Kansas, red, yellow,
and other colors, with even white bands, affords blocks over 1 foot
long and 6 to 8 inches wide, and really merits the attention of workers
in ornamental stone, as it is unrivaled in the world for banded jasper.
Bloodstones in
beautiful specimens with the red markings very fine are found at
Chatham county, Georgia. Some fine heliotropes from here are in the
cabinet of W. W. Jefferis. Heliotrope was formerly found in veins in
slate at Blooming' Grove, Orange county, New York. Some very fine
pieces have been found near the Willamette river, Oregon, and of fine
quality near the South park, Colorado, and below the Uncompahgre, near
Grand river.
Basanite was
found by Dr. Horton(a) at Canterbury and Cornwall, New York. It is also
sparingly found in nearly all the drift north of New York City, and in
that of the Delaware river from Easton, Pennsylvania, down to the
State line.
Gold quartz.—The
gold found in California quartz is worth about $16.50 per ounce, but
jewelers will give willingly from $20 to $30 for each ounce of gold
contained in such material as they can use. The price of specimens
varies according to their beauty from $3 to $40 per ounce of quartz.
The specific gravity of the mineral is taken, after which the gold
value is ascertained by a table called Price's table. The amount of
this material in the rough sold for jewelers' purposes is variously
estimated at from $40,000 to $50,000 per annum, $1,000 to $2,000 worth
being often purchased at one time. One lapidary at Oakland, who employs
several assistants, purchased nearly $10,000 worth within one year, and
a large jewelry firm in San Francisco, during the same time, purchased
nearly $15,000 worth of this material.
Great
care must be taken in the selection of the quartz. The stone used must
be large enough to bear the rough treatment of the diamond saw and
the.lap wheel of the polisher; all of the ore is friable, and some of
it crumbles to pieces while undergoing these processes. For the same
reason all the pieces set in cabinet work are small; the saw hanging in
the gold in the slitting prevents the cutting of large pieces, as the
wafer like slabs are apt to be broken by this resistance while being
separated from the block. Pieces 4 by 2 inches are quite rare, although
fine pieces 4 inches square are at times seen.
Rarely
more than one-half of the ore purchased finds its way into the mounting
owing to this breakage and the trimming into shape. Nearly all the
cutting of this material is done at Oakland, California.
a "Geological Survey of New York," 1840.
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