Alexandrite was discovered in 1830 in Russia’s Ural Mountains and is one of the rarest gemstones to source, particularly in large sizes. Because of its scarcity, alexandrite is a relatively expensive member of the chrysoberyl family. It shares its status as a June birthstone with cultured pearl and moonstone.
- Mineral: Chrysoberyl
- Chemistry: BeAl2O4
- Color: Bluish green in daylight, purplish red in incandescent light
- Refractive Index: 1.746 to 1.755
- Birefringence: 0.008 to 0.010
- Specific Gravity: 3.73
- Mohs Hardness: 8.5
Alexandrite, with its chameleon-like qualities, is a rare variety of the mineral chrysoberyl.
Its color can be a lovely green in daylight or fluorescent light, changing to brownish or purplish red in the incandescent light from a lamp or candle flame. This is a result of the complex way the mineral absorbs light.
Alexandrite is also a strongly pleochroic gem, which means it can show different colors when viewed from different directions.