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name:
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Alexandrite
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| gemstone variety:
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Chrysoberyl
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| trade name 1:
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Alexandrite
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| trade name 2:
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| trade name 3:
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| basic colour:
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green
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Colour :
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green and red
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Quality :
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most important is a good colour change from green in
daylight to red in incandescent or candle light. A balanced
combination of a good colour change and few inclusions is
considered best.
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History :
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Alexandrite was first discovered in the Urals in 1833
and was named after Czar Alexander II. In the Czarist Era
the Russians were proud of this national stone because the
main colours of the Russian army were green and red. After
the Bolshevik Revolution in 1917, the mining rate of
Alexandrite and other Russian gemstones fell to zero. After
the pull down of the Iron Curtain, mining production started
again. 1987 a new find of Alexandrite was made in Brazil at
a locality called Hematita.
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Curiosities / Saga :
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Countrys of Origin :
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Russia, in the emerald mines at the Takowaja in the
Urals, 90 km east-north-east from Ekaterinburg; Brazil and
Sri Lanka
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Birthstone :
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June - Alexandrite
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Hardness :
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8.5
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Treatment :
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none
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Size :
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normally small stones from 0.10 - 0.50 carats.
Alexandrites of 2.00 carats or more in good quality are
exceptionally rare!
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Specific gravity :
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3.70 - 3.75
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Chemical Composition Formula :
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Al2BeO4 + Cr2O3
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Chemical Composition Name :
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Chrome- bearing aluminium- beryllium- oxide (chrome-
bearing chrysoberyl)
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Crystal system :
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rhombic
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Light refraction :
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1.746 - 1.756
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Double refraction :
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0.010
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