Gemstone Feature: Alexandrite

By July 29, 2017All

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.

Source: GIA