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Cat's-eye was undoubtedly known to the ancients. It was described
by Solinus as "a gem picked up in the bed of the Euphrates,
in appearance like the Proconesian marble, except that in the middle
convexity of the stones a green thing shines through like the pupil of
an eye." This more precisely applies to the quartz cat's-eye.
In Brazil, the normal chrysoberyl is found transparent, translucent
or semi-opaque, and without the cat's-eye. It is called
''Brazilian chrysolite" and is very like the true yellowish green chrysolite
or peridot, but lacks its brilliance. Perfectly transparent stones
even in Brazil, where they are valued for their color rather than the
chatoyant ray, are very rare. When found, they are generally cut en
cabochon, with convex gold at their back to increase the lustre.
The newly discovered "spodumene" of North Carolina has yellowish
green crystals so like the "Brazilian chrysolite" that in gem
form they might easily be mistaken for each other, though spodumene
is inferior to chrysoberyl in hardness and of entirely different con-
stitution.
The singular alexandrite is a third variety of chrysoberyl. It
was so called because discovered in the Ural Mountains within the
Czar's dominions on the day in 1830 when Alexander II. of Russia
attained his majority. Since then, larger and more beautiful specimens
have turned up in the world's great jewel-box, Ceylon. The
finest of these are transparent, very dark, olive green by day and
rich raspberry red by artificial light. Some might be described as a
clean pistache or tourmaline green by day and purplish pink or
amethystine by night. Usually one of the colors, either green or red,
is pale and indefinite, if the stone is shallow, or else too dark, if thick.
Alexandrite is not effective unless rather large and deep, skillfully
cut and of the best color. A stone that is the correct hue both by
night and by day is extremely rare. Yet the writer possesses one
such, a Ceylon stone. Its green by day is always olive or sage, the
sure sign of Cingalese parentage, while its gala color is a magnificent
red, sweeping the whole surface in brilliant flashes. This is
perhaps the gem alexandrite of Ceylon, not so effective by day, in
its dull sage green, sometimes mixed with brown, but a wonder of
burgundy red by night, while the Russian gem at its best is a very
pale emerald by day and a columbine pink at night.
Not only are the Russian crystals smaller than the Cingalese,
but the green is frequently uncertain, bluish, without depth or allurement,
nor is the red satisfactory. All the same the Russian is favored
both by mineralogists and jewelers ; and when of a light clear emerald
green by day and a purplish pink or amethystine ruby by night,
it is
a striking gem. The Russian, however, is exceedingly defective,
flaws interfering with its brilliance, while the Cingalese is apt to
be structurally far more perfect.
Strongly dichroic, even trichroic, the secret of the strange
changes from green to red, the alexandrite appeals to Russia not
only through its first appearance there, but because it exhibits the
national military colors. Still it is odd, as a rule, rather than beautiful,
high-priced largely because it is scarce, and growing scarcer
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