- Alexandrite from the Ural Mountains in Russia is green by daylight and red by incandescent light.
- The mineral chrysoberyl is found in transparent yellow to greenish yellow color, but only two varieties are widely known as gemstones: cat’s eye and alexandrite.
- Because of their rarity and the color change capability, "ideal" alexandrite gems are some of the most expensive in the world.
- Alexandrite is the extremely rare variety of the mineral chrysoberyl that actually changes color from green, in daylight, to red, in incandescent light.
- Synthetic alexandrite is used as an active laser medium. Alexandrite laser crystals tend to be round, with a pale brown tint.
- It was discovered in 1830 in Czarist Russia. Since the old Russian imperial colors are red and green it was named after Czar Alexander II on the occasion of his birthday.
- Alexandrite alternates with pearl and moonstone as the birthstone for the month of June.
- Alexandrite can be found in jewels of this period. Master gemologist George Kunz of Tiffany was a fan of alexandrite and the company produced rings featuring fine alexandrite in the late nineteenth and early twentieth century, including some set in platinum in the twenties. Victorian jewelry from England also features sets of small alexandrites.
- According to a widely popular but controversial story, alexandrite was discovered by the Finnish mineralogist Nils Gustaf Nordenskiöld, (1792–1866) on the tsarevitch Alexander's sixteenth birthday on April 17, 1834 and named alexandrite in honor of the future Tsar Alexander II of Russia.