mineral

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

AI-generated identification · may be incorrect

Hardness: 5-6 (Mohs scale); Color: Sky blue to blue-green; Luster: Waxy to subvitreous; Crystal structure: Triclinic; Cleavage: Good to perfect (though rarely seen in cryptocrystalline form); Specific gravity: 2.60–2.90

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

Identified March 8, 2026More mineral →

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Physical properties

Formation & geological history

Secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. Usually found in arid regions within volcanic or sedimentary rocks rich in copper and aluminum.

Uses & applications

Primarily used as an ornamental stone, in jewelry (cabs, beads, inlay), and as a collector's gemstone. Also historically used as a pigment and for cultural amulets.

Geological facts

Turquoise is one of the oldest gemstones used by human civilizations, dating back to ancient Egypt and the Persian Empire. The name comes from the French 'turquois' meaning 'Turkish,' because the stone reached Europe via Turkey.

Field identification & locations

Identify in the field by its distinctive 'robin's egg' blue color and presence in arid, copper-rich mining regions. Often associated with limonite (brown matrix) or quartz. Natural specimens are porous; many commercial stones are stabilized with resin.