Turquoise

Turquoise, AL₂(OH)₃PO₄H₂O+Cu, igneous (volcanic) mineral containing aluminum, copper, and phosphorus, found in arid regions of the earth, especially Iran, the Sinai Peninsula, and the North American Southwest. Varying in color from light blue (gem quality) to greenish-gray, turquoise has been used to make jewelry for thousands of years. Native American tribes of the Southwest, especially the Navajos, became skilled in fashioning turquoise-and-silver jewelry.