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Alexandrite Gemstone Information

Alexandrite is a colour change variety of chrysoberyl discovered in 1830 in the Ural Mountains of Russia. It was named after the ruling Czar of the time, Alexander II. The colour changes from green in natural daylight to red in incandescent light and candlelight. In good quality gemstones the colour difference is stunning but extremely rare and highly expensive. Most Alexandrite on the market will show paler colours with greyish and brownish tones, where good examples are more likely to be synthetic (created) Alexandrite.

The Ural mountain deposits of Alexandrite have been mined-out and although rare, it is mined in other source locations including, Africa, Brazil, Burma, India, Madagascar, Sri Lanka, Tasmania and the USA.

Physical Properties

Stone type:
A variety of Chrysoberyl
Crystal System:
Orthorhombic
Chemical Composition:
Beryllium Aluminium Oxide, BeAl2O4
Colour:
Green in sunlight (daylight), red in incandescent light (filament light bulb) and candlelight.
Lustre:
Bright vitreous
Pleochroism:
Trichroic, strong in dark stones, weak in light stones.
Dispersion:
Low
Hardness:
8½ on the Mohs' scale of hardness
Toughness:
Excellent
Cleavage:
Indistinct
Density in gm/cc:
3.71 to3.75
Double refraction:
Yes
Refractive index:
1.74 to 1.76

Common Treatments

Alexandrite is not normally treated.

Synthetic Alexandrite is produced in the Laboratory (Lab-created), it has the same physical and optical properties as the natural stone.

Lab-created spinel has been produced to simulate Alexandrite.


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