mineral

Turquoise

CuAl6(PO4)4(OH)8·4H2O

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

Identified June 8, 2026More mineral →

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Physical properties

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

Formation & geological history

Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is a secondary mineral usually found in arid climates within volcanic rocks or phosphorus-rich sediments.

Uses & applications

Primarily used as a gemstone for jewelry (beads, cabochons, inlays) and as a decorative ornamental stone. Highly valued in Native American and Middle Eastern cultures.

Geological facts

Turquoise was one of the first gemstones ever mined, with some Egyptian mines dating back to 3000 BCE. Its name comes from the French 'turquois', meaning 'Turkish', as it first reached Europe via Turkey.

Field identification & locations

Identified by its distinctive robin's egg blue color and waxy texture. To differentiate from fakes like dyed howlite, look for color consistency in cracks; real turquoise may have a brown or black limonite/iron oxide matrix.