416 PRECIOUS STONES IN THE UNITED STATES.
similar
volcanic rock, containing a carbonaceous shale, was found in Elliott
County, Kentucky, by Mr. J. S. Diller; and the possibility of diamonds
being found there, was suggested by Professor Carvill Lewis, and led to
a systematic search by Mr. Diller and the writer, under a mission from
the United States Geological Survey. Diamonds were not found, and the
shale was found to contain only l-35th as much carbon as the South
African rock. Still there is a possibility, that the eruptive rock may
have penetrated richer layers of the carboniferous and Devonian rocks
elsewhere.
Of
the corundum or sapphire gems, more than fifty have been found at the
Jencks Mine, Franklin, North Carolina, where corundum mining was
carried on some years ago, and has recently been resumed Jto supply
mineral for a grinding or polishing substance. Fully one-half of these
were really gems in every sense of the word. Some ruby-red ones were of
a fair color. The blue sapphire and some fine violet-blue, light red,
pink, and yellow sapphires, were also found. None of these gems had a
higher value than a hundred dollars. An emerald-green sapphire
(Oriental emerald), measuring 4 by 2 by ij inches, that would furnish
from 80 to 100 carat weight of gems, the largest being about 20 carats
in weight, is now in the cabinet of Mr. Clarence S. Bement, with the
choicest crystals found at this mine. The gem is one of the rarest
known. It will not be cut, however, since its owner prizes it much more
highly in its natural state. This locality has also furnished some fair
cabochon rubies, weighing over one carat. Vernon, New Jersey,
has furnished some crystals of sapphire and ruby, which are brilliant
though opaque, thus possessing little commercial value. The largest
known crystal of sapphire came from the Jencks Mine about 1872. It
weighed 312 pounds, and was both red and blue, ruby and sapphire, in
color. It is now in the Shepard collection at Amherst College, and was
considerably injured in the disastrous fire of 1882. Rubies and
sapphires, always more or less opaque, have been found at many
localities in North Carolina and Georgia.
The
finest sapphires for gems, are collected by the miners from the
sluice-boxes of the placer mines near Helena, Montana. The gems are
usually light green, blue, red, and all the intermediate shades. One of
these rough crystals is shown in Fig. 2 of the plate. Often they are
blue, as viewed in one direction, and red when seen in another.
Frequently all the colors would assume a red hue by artificial light. A
very interesting piece of jewelry was recently made from these stones
in the form of a crescent. At one end, as seen by daylight, the stones
were red, shading to a bluish-red in the centre, and finally into blue
at the other end ; but by artificial light the color of all turned red.
A few small gems less than cne carat in weight, have come from the same
place that were truly ruby red and sapphire blue. Of the latter color,
perfect gems have been found here up to nine carats in weight. By
artificial light these ar« intensely brilliant.
The
colored plate shows (Fig. 3) the first sapphire ever found in its •
original matrix. It consists of the stone from which a kernel of blue
sapphire had dropped out. This kernel was then cut, and replaced in its
original matrix. A white band running across the centre of both, shows
conclusively that it belonged there. It was mined by Colonel C. W.
Jencks, at Franklin, North Carolina. Near this place, brown crystals of
sapphire have been found, in which, when they are cut en cahochon, so
that the dome of the cut'stone is parallel with the perpendicular axis
of the crystal, an asteria effect is produced, but not as fine as the
Oriental.
Spinels
of a smoky blue, velvet green, and dark tinted claret-color have been
found in gems weighing about two carats each, near Hamburg, New Jersey.
Some fine ones weighing about two carats each, were unearthed in San
Luis Obispo, California. Twenty years ago, somewhere between Monroe and
Southfield, Orange County, New York, a deposit was known only to two
persons, now deceased. The locality was worked- secretly for some years
by
