Petalite: Petalite is a lithium aluminum silicate that is an important ore of lithium. This mineral forms, rarely, as small crystals, which are commonly twinned. More often, petalite forms as large, cleavable masses. It may be white, grey, pinkish, yellow, or colorless. It is transparent to translucent, with a vitreous to pearly luster, and fuses with difficulty. It forms in very coarse-grained, acid igne (read full)

Turquoise: Turquoise is a hydrated phosphate of copper and aluminum in the Phosphates, Arsenates, Vanadates group, with a triclinic crystal system. It rarely occurs as prismatic crystals. It is usually found as light-blue or green masses, nodules, and veins, sometimes filling cavities in various rocks. When it occurs as thin strips, it is tighter and brightly-colored at the center, lighter and porous on the (read full)