sometimes been relegated to obscurity by the caprices of
fashion. Its chemical constituents are alumina and glucina,
with traces of some other substances for coloring agents; it is
transparent to translucent, occasionally opalescent internally,
displays a remarkable play of colors, and is double refracting.
Its glittering crystals exhibit different shades of green, brown,
yellow, and white colors ; the transparent yellowish specimens,
cut with facets, and the opalescent varieties, en cabochon, are
those most frequently used for ornamental stones.
The term cymophane, meaning " to appear like a wave of
light," is given to a variety of the chrysoberyl when it has the
appearance of enclosing rays of light, which seem to be floating
in the interior of the stone, a phenomenon supposed to be the
result of blue reflections emanating from a milky-white substance ; or the gem may be compared to a drop of water with
a beam of light imprisoned within. Examples of this variety
of the chrysoberyl are seen in the South Kensington Museum.
Alexandrite. — This red and green variety of the chrysoberyl was named for Alexander I., Emperor of Russia, who
adopted these hues for the imperial colors. It affords a good
example of dichroism, presenting a dark green by daylight,
which changes to a columbine red in the evening or by artificial light. Its discovery in the Urals is of recent date, though
it is said about one-third of all those sold are from Ceylon, a
large per cent of them weighing over sixty carats.
Cat's-eye. —This variety of the chrysoberyl is the true cat'seye and entirely unlike the chatoyant quartz erroneously called
by this name. It seems to be a sub-translucent form of
cymophane, and partly the result of art or the form of cutting ;
its peculiar play of colors is attributed to minute internal
striations. It was called by some of the nations of antiquity
"oculus solis," eye of the sun, and is at the present day a
