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PRECIOUS STONES.
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own
term from it; and further, attributed to it the property of being an
antidote for intoxication. It is sometimes designated "occidental
Amethyst" to distinguish it from the very rare amethyst-coloured
Corundum, to which the term " Oriental Amethyst " is applied. It is
often rather turbid in colour, and not infrequently alternate layers of
colourless and amethystine Quartz may be seen in one crystal. Such
kinds as are transparent and of a good even colour suitable for use as
gems, are designated "precious Amethyst." Good specimens were held in
very high repute by the ancients—too valuable to be engraved as most of
their precious stones were. Now, however, it is of little value, though
even a hundred years ago it was much prized, and Queen Charlotte's
necklace of fine Amethysts was valued at ±'2,000; now the very best
qualities are only worth 10s. a carat, or less.
In
addition to its presumed virtue in allowing of liberal potations
without unpleasant effects, it was reputed to enable the wearer to
interpret dreams, maintain presence of mind, and cast off evil
thoughts, and so on.
It
was the eighth stone of Aaron's breastplate, and it has from its use as
a ring stone by Bishops of the Roman Church, been called "Bishop's
Stone."
Amethyst exhibits a feeble dichroism, the images being a reddish-violet and bluish-violet respectively.
It
usually occurs in short prisms with the two rhom-bohedra, or even
without the prism form at all. As indicated in the section dealing with
the origin of precious stones in general, Amethyst is often found in
vapour cavities in lavas, sometines lining the unfilled portion of an
Agate; it also occurs similarly to vein Agate, deposited in fissures by
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