lapis lazuli (lăpˈĭs lăzˈŏlē) [key], gem, deep blue, violet, or greenish blue in color and usually flecked with yellow iron pyrites. It is composed of lazurite, a complex sodium aluminum silicate, mixed with other minerals, and is usually found in masses, rather than in crystals, in metamorphosed limestones. Sources of supply are Afghanistan, Chile, Siberia, upper Myanmar, California, and Colorado. It was formerly made into vases and bowls and has been used from ancient times for beads and small ornaments. It was also extensively used in mosaics and was the "sapphire" of the ancients.