Turquoise

Turquoise is a hydrated phosphate of copper and aluminum. It is a secondary mineral occurring in veins in association with aluminous, igneous or sedimentary rocks that have undergone considerable alteration, usually in arid regions. Turquoise is often mottled with veinlets of brown limonite or black manganese oxide.

Chemical composition CuAl(PO4)4(OH)8·4(H2O)
Color Sky blue, blue-green
Lustre Waxy (massive), glassy (crystals)
Hardness 5 - 6
Crystal system Triclinic
Origin Egypt’s Sinai Peninsula, Persia, Turkestan, Tibet, China, Russia, Iran, USA
Healing properties*

Turquoise possesses a strong capacity to regenerate and protect, providing overall health and strength. Calms the nervous system.
Folklore

The Zuni people of New Mexico wore turquoise to protect themselves from demons. The Navajo believed the blue stones were pieces of sky that had fallen to earth.