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

Turquoise

Hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O

AI-generated identification · may be incorrect

Opaque vivid blue-green, typically waxy to subvitreous luster, cryptocrystalline/triclinic; Mohs hardness 5–6, specific gravity about 2.6–2.8, with indistinct cleavage. Brown matrix or veining is common, as visible here.

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Physical properties

Opaque vivid blue-green, typically waxy to subvitreous luster, cryptocrystalline/triclinic; Mohs hardness 5–6, specific gravity about 2.6–2.8, with indistinct cleavage. Brown matrix or veining is common, as visible here.

Formation & geological history

Forms as a secondary phosphate mineral in arid, copper-rich, weathered zones above sulfide deposits, commonly replacing host rock. Deposits range from ancient Precambrian occurrences to much younger weathering environments.

Uses & applications

Used as a cabochon gemstone, beads, inlay, and ornamental material; historically important in jewelry and cultural objects. Stabilized, dyed, reconstituted, and imitation turquoise are also widely sold.

Geological facts

Common localities include Iran, the U.S. Southwest, Mexico, China, Chile, and Egypt. Natural turquoise is porous and may darken or absorb oils; heat, chemicals, and prolonged moisture can damage it.

Field identification & locations

Identify by its intense blue/green color, opaque appearance, brown or black matrix, moderate softness, and porous feel; it should not scratch quartz. The specimen appears tumbled or polished and may be stabilized.