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GEMS AND PRECIOUS STONES.
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311
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VIRGINIA.
A
specimen of amethyst from a locality 1 mile west of Minnieville, Prince
William County, Va., has recently been acquired by the United States
National Museum. This amethyst was found in 1902 in a cultivated field,
and was recently brought to the attention of Farnham E. Briggs, of
Minnieville. Mr. Briggs has prospected around the locality, but only
found a few colorless quartz crystals and failed to find other
amethyst. The specimen weighs over 3 pounds, measures 6 inches across
the prism zone, and is 5 inches high. The crystal has been split so
that a thickness of 3 inches only remains. The whole specimen is not
amethyst; the interior consists of colorless to partly fractured
quartz crystal nearly 4 inches in diameter, incrusted with groups of
amethyst crystals from half an inch to 1-1/4 inches thick. On one side
these groups of crystals have grown into one larger amethyst crystal
with a face 3 inches across around the prism zone, but terminated by
several pyramidal points. The faces of the amethyst crystals are
somewhat dimmed by etching or wear, and part of the crystals are rather
badly flawed. Most of the amethyst crystals have a beautiful bright
purple color, grading from dark to pale. As usual the color is darkest
near the points of the separate crystals. This amethyst is of interest
chiefly as a specimen and would yield only small flawless gems. The
richness of the color and the size of the crystals, however, are
sufficient to justify further efforts to locate the deposit from which
the specimen has been obtained.
Amethyst
has been found in the region of Trevilians, Louisa County, Va. One of
the prospects, on the land of A. J. Rudinger, 4 miles southwest of
Trevilians, was visited. Crystals are also reported on the places of
Capt. William Overton and J. J. Boxley in the same general region. On
the Rudinger land amethyst crystals have been found at two places loose
in the soil of cultivated fields about a quarter of a mile north of the
house. At one of these places the crystals were found in an area about
40 feet in diameter. The soil at this place is reddish and sandy,
resulting from the decomposition of a granitic rock inclosing diorite.
An outcrop of quartz has covered the surface with massive quartz debris
for a distance of nearly 100 feet in a S. 60° W. direction beginning a
few yards southwest of where the amethysts were found. Soapstone
borders the granite and diorite on the southeast. About two quarts of
crystals have been picked up at this locality, ten or a dozen of which
have good color. The others range from paler purple to almost colorless
quartz. The crystals are mostly small, not many measuring over an inch
thick. The best ones have a fine dark purple color, which is not evenly
distributed or clear through the whole crystal.
During
July, 1915, Mr. Rudinger dug a trench 12 feet long and 5 feet deep at
this prospect. The amethyst vein was located and about half a bushel of
crystals are reported to have been taken out. Seven of these crystals
were sent to the Survey for examination. They were of about the same
size as those found on the surface, but were of better color and
quality. Most of them were not perfectly clear or flawless, but would
cut into beautiful beads. One or two of the crystals would yield small
flawless gems of rich purple color.
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