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Alexandrite
Discovered on the birthday of Czar Alexander in 1830, Alexandrite
is the most valuable form of the mineral chrysoberyl, which also
appears as cats eye or as an inexpensive faceted gem of an unusual
greenish hue.
The fortuity of the discovery of Alexandrite on the Czar’s birthday
was considered manifold because the colors displayed by this unusual
stone mirror the imperial Russian colors red and green. When viewed
under sunlight or fluorescent light, Alexandrite appears medium
to bluish green, when seen by candlelight or incandescent light,
it appears violet red.
This effect is not unique to Alexandrite, many gem types display
color change (sapphire, garnet, apatite, tourmaline, obsidian, etc…)
however the degree of color change exhibited by these highly valued
gem stones is the most extreme ever encountered in natural gems.
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This quality is best
utilized in Alexandrite earrings, which can catch different light
sources and truly show the vibrancy of Alexandrite’s color-change
property. Alexandrite rings are also a popular option as it is a
very tough stone. Its hardness is only transcended by rubies, sapphires
and diamonds. Alexandrite cats eyes make particularly stunning signet
rings and are a powerful display of a unique sense of style. In
the cat’s-eye form, fine quality Alexandrite should be semi-transparent
with a sharp exhibition of the white eye.
Since its discovery Alexandrite has rapidly grown in popularity,
leading to the near depletion of the original Russian sources. Today
the world’s major source of alexandrite is in the state of Minas
Gerias, Brazil. In 1987, at the Lavra de Hematita mine, the world’s
largest deposit of alexandrite was found. In 1993, another source
of this extraordinary gemstone was found near the Tanzania-Mozambique
border.
The degree of color change is the first and most important consideration
when evaluating the value of Alexandrite. Low quality stones will
present a less dramatic change of color, partially retaining some
of the green color or appearing brown under incandescent light.
The evaluation of Alexandrite should be performed in a dark room
under a single light source (i.e. a candle or a light bulb).
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