Rock Identifier
Turquoise (Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O) — mineral
mineral

Turquoise

Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

AI-generated identification · may be incorrect

Typically blue-green to green, waxy to subvitreous luster, opaque, cryptocrystalline, Mohs hardness 5–6, and specific gravity about 2.6–2.9; the dark spiderweb-like matrix is host rock, likely limonite or other iron-rich material.

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Physical properties

Typically blue-green to green, waxy to subvitreous luster, opaque, cryptocrystalline, Mohs hardness 5–6, and specific gravity about 2.6–2.9; the dark spiderweb-like matrix is host rock, likely limonite or other iron-rich material.

Formation & geological history

Forms as a secondary phosphate mineral in arid, oxidized zones of copper deposits, commonly replacing aluminum-rich rocks. Deposits are generally geologically young relative to their host ores, often Cenozoic to older hydrothermal systems.

Uses & applications

Used for cabochons, beads, carvings, and ornamental objects; historically important in jewelry and ceremonial art. Fine natural turquoise is valued more highly than stabilized, dyed, or reconstructed material.

Geological facts

The specimen appears to be natural nugget or rough turquoise with attractive matrix, though treatment cannot be confirmed visually. Color and matrix patterns vary strongly by mine.

Field identification & locations

Identify by its blue-green color, opaque waxy surface, moderate hardness, and copper-related occurrence; it should not fizz with dilute acid. Major sources include Arizona, Nevada, Iran, China, Mexico, Chile, and Tibet.