Cordierite (Iolite Gem)

About Cordierite (Iolite Gem)

The gem variety of the mineral cordierite. Its strong trichroism shows three distinct colors from different angles: blue, violet, and yellowish-gray. Viking navigators used thin iolite slices as polarizing filters. It is found in Sri Lanka, India, and Madagascar. It is relatively affordable. The best color is a rich sapphire-like blue. It is hard enough for everyday jewelry. It does not require treatment. It is also called dichroite and water sapphire. It has been known since the Viking Age.