
This gem was first found in Takavaya, in the Ural Mountains of Siberia, in 1830, on the anniversary of the birth of Alexander II, Czar of Russia, and because of that circumstance and since green and red, the colors of the gem, are also Russia's national colors, it was named, in honor of the Czar, Alexandrite.
The mineral composing the gem is Chrysoberyl, which resembles beryl in composition but is known for its hardness, being graded 8.5. The alexandrite shows normally an emerald green color, but changes by artificial light to a beautiful red, and has, therefore, the unique property of resembling somewhat "an emerald by day and a ruby by night." Much of the mineral is found, but transparent pieces which can be used as gems are of very rare occurrence, and the Alexandrite is therefore very valuable, besides being unique in the beauty of their double colors.
A more common variety of chrysoberyl is the gem known as Cat's eye, which always shows the familiar band of color in the center. Most of the stones are cut cabochon, in order to best display this mark. Most of the cat's eyes now come from Brazil and Ceylon.