Chemical Composition : BeAl2O4 Beryllium Aluminum Oxide + traces of Chromium
Hardness : 8.5
Specific Gravity (Density) : 3.75 (g/cm3)
Refractive Index : 1.745 – 1.756 Biaxial (+)
Alexandrite is a rare green (chromium-bearing) gem variety of Chrysoberyl known for its color change effect. Its color depends on the light hitting it; green, blue-green or pale green in daylight; mauve, violet to purplish or red in incandescent light. This distinct pleochroism and its rarity accounts for its desirability and high value. Alexandrite is also available as a cat’s eye gem with the same color change effect.
Alexandrite was originally reported from Emerald mines (Izumrudnye Kopi; Malyshevskoye deposit), Malyshevo, Ekaterinburg (Yekaterinburg; Sverdlovsk), Sverdlovskaya Oblast’, Urals Region, Russia. It is also known from sources in Australia, Brazil, India, Madagascar, Myanmar (Burma) Sri Lanka, Tanzania, New Mexico, USA and Zimbabwe. The rarest and most highly prized gems come from the Urals Region of Russia.