Labradorite is a feldspar mineral. It occurs as clear, in shades white to gray. They may vary from block shaped to lath shaped grains. Labradorite occurs in mafic igneous rocks and is the feldspar variety most common in basalt.
Labradorescence is an optical phenomenon which occurs in large crystal masses in anorthosite. It shows a play of colors called as The labradorescence, or schiller effect. Gemstone varieties of labradorite exhibiting a high degree of labradorescence are called spectrolite.