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Fine quality
alexandrite displays a colour
change (alexandrite effect) dependent upon
the light source under which it's viewed.
Alexandrite results from small scale replacement of aluminium by
chromium oxide,
which is responsible for alexandrite's characteristic green to red
colour change. Alexandrite from the
Ural Mountains
in
Russia is green
by daylight and red by incandescent light. Other varieties of
alexandrite may be yellowish or pink in daylight and a
columbine or
raspberry red
by incandescent light. The optimum or "ideal" colour
change would be fine emerald green to fine purplish red, but this is
exceedingly rare.
00000Because of their
rarity and the colour change capability,
"ideal" alexandrite gems are some of the most expensive in the world.
The are many lesser quality alexandrite on the market, usually pale
green and not displaying a noticeable colour change. |
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