One
of the largest géodes of amethyst was brought into England in 1819,
weighing one hundred ami fifty pounds; it was two feet long and
fourteen inches'broad, and contained most magnificent crystals, of the
deepest violet color. On account of having been set down at too low a
price at the custom-house, which was sixty-five pounds sterling, it was
confiscated.
COMMON QUARTZ.
But a few varieties of the common quartz are used in jewelry, which, are : the Rose Quartz, the Cat's-eye, the Prase, and the Avanturine.
Rose Quartz.
This
mineral generally occurs massive ; it is semi-transparent, and
translucent on the edges ; has a vitreous lustre ; conchoidal and
splintry fracture ; is of a rose-red color ; sometimes giving a lustre
of mother-of-pearl. It scratches glass ; has a specific gravity of 2-64 to 2"67 ; its color, which is derived from the oxide of manganese, becomes paler before the blowpipe.
Rose
quartz occurs in gangues of granite and gneiss, particularly fine in
Sweden, Bavaria, Bohemia, and Siberia ; also a beautiful dark color in
New-Hampshire and Massachusetts.
Rose
quartz is cut and polished for jewelry ; such as rings, breastpins, and
snuff-boxes ; it is cut on a copper wheel with emery, and is polished
with rotten, stone and putty, on a tin plate, receiving the form of a
cabochon or
