mineral

Turquoise

Turquoise (Hydrated phosphate of copper and aluminium) - CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale); Color: Sky-blue, bluish-green, to apple-green; Luster: Waxy to subvitreous; Crystal structure: Triclinic (usually cryptocrystalline); Cleavage: Perfect but rarely seen; Specific gravity: 2.6-2.9.

Hardness: 5-6 (Mohs scale)
Color: Sky-blue, bluish-green, to apple-green
Luster: Waxy to subvitreous

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is secondary in origin, typically found in arid climates within volcanic rocks or sedimentary phosphate deposits. Geological age varies but most significant deposits are millions of years old.

Uses & applications

Primarily used as a gemstone in jewelry, decorative carvings, and inlay work. It has been highly valued for ornamental use throughout history in Persian, Egyptian, and Native American cultures.

Geological facts

Turquoise is one of the oldest known gemstones. The word 'turquoise' comes from the French 'turquois' meaning 'Turkish', as the mineral was first brought to Europe through Turkey from mines in Persia. It is the birthstone for December.

Field identification & locations

Field identification is based on its distinct robin's egg blue or greenish color and waxy appearance. Often found with a 'matrix' of brown or black host rock veins (limonite or manganese oxide). Major locations include Iran (Nishapur), Southwest USA (Arizona, Nevada), and China.

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