mineral

Turquoise

Turquoise - CuAl6(PO4)4(OH)8·4H2O

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

Identified June 28, 2026More mineral →

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Physical properties

Formation & geological history

A secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is typically found in arid regions, often occurring as veins or crusts in altered volcanic rocks or aluminous sedimentary rocks.

Uses & applications

Primarily used as an ornamental stone and gemstone in jewelry (rings, necklaces, bracelets). Historically used in amulets and architectural mosaics.

Geological facts

Turquoise is one of the oldest known gemstones and was highly prized by ancient Egyptians, Persians, and Native Americans. The name comes from the French 'turquoise', meaning 'Turkish', as the stone first reached Europe through Turkish trade routes.

Field identification & locations

Identify in the field by its characteristic robin's-egg blue color and waxy appearance; it is often found alongside copper deposits. Collectors should look for 'matrix' (veins of host rock) which adds to authenticity, but be wary of dyed howlite or plastic imitations which feel lighter or warmer to the touch.