 One
of the most fascinating gemstones throughout history is alexandrite:
a gem variety of the mineral chrysoberyl that actually changes
color from green in daylight to red in incandescent light. The
first time you see it, it is hard to believe your eyes! Gems
that show special optical effects are known as phenomenal stones.
Chrysoberyl dominates this category, because not only is alexandrite
the most spectacular color change gem, cat's-eye
chrysoberyl has the most dramatic eye. Alexandrite has a
distinguished and glamorous past: it was discovered in 1830
in Czarist Russia. Since the old Russian imperial colors are
red and green it was named after Czar Alexander II on the occasion
of his coming of age.
 Alexandrite
can be found in jewels of the period as it was well loved
by the Russian master jewelers. Master gemologist George Kunz
of Tiffany was a fan of alexandrite and the company
produced many rings featuring fine alexandrite in the late
nineteenth and early twentieth century, including some set
in platinum from the twenties. Some Victorian jewelry from
England features sets of small alexandrites.
Alexandrite
is also sometimes available as an unset stone but it is extremely
rare in fine qualities. The original source in Russia's Ural
Mountains has long since closed after producing for only a
few decades and only a few stones can be found on the market
today. Material with a certificate of Russian origin is still
particularly valued by the trade. Some alexandrite is found
in Sri Lanka and Zimbabwe and Brazil but very little shows
a dramatic color change. For many years, alexandrite was almost
impossible to find because there was so little available.
Then in
1987, a new find of alexandrite was made in Brazil at a locality
called Hematita. The Hematita alexandrite shows a striking
and attractive color change from raspberry red to bluish green.
Although alexandrite remains extremely rare and expensive,
the production of a limited amount of new material means a
new generation of jewelers and collectors have been exposed
to this beautiful gemstone, creating an upsurge in popularity
and demand.
When evaluating
alexandrite, pay the most attention to the color change: the
more dramatic and complete the shift from red to green, without
the bleeding through of brown from one color to the next,
the more rare and valuable the stone. The other important
value factors are the attractiveness of the two colors - the
more intense the better - the clarity, and the cutting quality.
Because of the rarity of this gemstone, large sizes command
very high premiums.
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