Labradorite

Labradorite is a calcium-enriched feldspar mineral first identified in Labrador, Canada, which can display an iridescent effect (schiller).

Labradorite is an intermediate to calcic member of the plagioclase series. It has an anorthite (%An) percentage of between 50 and 70. The specific gravity ranges from 2.68 to 2.72. The streak is white, like most silicates.

Labradorite can display an iridescent optical effect (or schiller) known as labradorescence. The term labradoresence coined by Ove Balthasar Bøggild. Some gemstone varieties of labradorite exhibiting a high degree of labradorescence called spectrolite.