tained.
It is, however, held in solution in the hot waters of the Geysers of
Iceland, whose solvent power is supposed » to be due to the presence of
a small quantity of alkali and their high temperature. The Geysers have
covered the part of Iceland in their vicinity with a silicious sinter.
The pseudomorphons quartz, from North Carolina, contains fluids in large quantities in its cavities.
Two pieces of quartz rubbed together in the dark, emit a phosphorescent light and a faint empyreumatic odor.
AMETHYST.
This
gem has been known since, the earliest ages of Greece and Rome ; the
name is of Greek origin. The ancients believed that wine drank from an
amethyst cup would not intoxicate ; hence its name, expressive of that
belief-
from a, not;
to intoxicate. As re-
gards
the color, Pliny says: "ad riciniam crystalli descen-det albicante
purpurae defectu," purple gradually fading into white. This is not,
however, the only amethyst of the ancients; the violet-colored
sapphire, the violet fluor spar, (" sculptaris faciles," easily
graven—Pliny,) and some other purple" species were designated by the
same name. It has also been supposed that 'garnet came under the same
denomination. This name occurs in Scripture, being that of the ninth
stone in order on the high priest's breast plate of judgment, with the
name Issachar engraved thereon. Amethysts were always used for
engraving. The bust of Trajan, in the Royal Library, at Paris, and the
Apollo Belvidere, the Farnese Hercules, and the group of the Lao-coon,
are splendid specimens of it. It occurs massive in boulders, or in
hexahedral prismatic crystals, terminated by hexahedral pyramids. Its
crystals are rarely as distinct as those of quartz, being, for the most
part, latterly aggre-
