Turquoise (CuAl₆(PO₄)₄(OH)₈·4H₂O) is a hydrous copper aluminum phosphate, prized for its sky-blue to apple-green color since prehistoric times. Persia (Nishapur, Iran), Hubei (China), and the American Southwest (Sleeping Beauty Mine, Arizona) supply iconic gem-quality material. Color depends on copper content (sky-blue) vs. iron (greenish).
Key Facts
- Mohs hardness 5–6.
- Triclinic; usually massive, microcrystalline aggregates.
- Sky-blue color from Cu²⁺ + Al; green tones from Fe substitution.
- Color may “turn” green with prolonged skin contact (oils + heat).
- Used since 5,000 BCE in Egyptian, Persian, Aztec, and Native American jewelry.
Notable Localities
Houzhuang (Hubei) is a major Chinese turquoise source. Nishapur (Iran), Sleeping Beauty Mine (Arizona), and Lavender Pit (Bisbee, Arizona) supply iconic specimens.
Found at these Localities
- Bisbee (Warren District) (比斯比铜矿)
- Hubei (湖北)
