An opaque sky-blue semiprecious gemstone. Turquoise is composed of a hydrated basic copper aluminum phosphate mineral. It was used for beads as early as 5000 BE in Mesopotamia. Major deposits were worked in Iran (Nishapur, Juh-e Zar, Kuh-i-Firouzeh) and on the Sinai Peninsula. Turquoise is also found in Siberia, Turkestan, Germany (Saxony), France, England (Cornwall), Australia and the U.S.(Mexico, Arizona, Colorado, California, New Mexico). Turquoise can be blue, greenish blue or green with inclusions of red sandstone. Turquoise is used for cabochon jewelry, inlays, beads and small carvings.
Synonyms and Related Terms
turqoius; calliana; callais; Mecca stones; Türkis (Deut.); turquesa (Esp., Port.); turquoise (Fr.); turkoise (Ned.)
Triclinic system, opaque, dense, cryptocrystalline to fine-grain massive.
Fracture is conchoidal. Luster = waxy. Streak = white to pale-green.
Soluble in hot hydrochloric acid.
|Composition||CuAl6(PO4)4(OH)8 - 4H2O|
|Mohs Hardness||5 - 6|
|Refractive Index||1.61; 1.62; 1.65|
Hazards and Safety
Stone can discolor to green with wear or contact with oils and grease
Mineralogy Database: Turquoise
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