mineral

Turquoise

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

AI-generated identification · may be incorrect

Opaque blue-green, typically waxy to subvitreous luster; Mohs hardness 5–6, triclinic structure, uneven fracture, and no prominent cleavage. Dark matrix veining suggests natural host-rock inclusions, though dyeing or stabilization is possible.

Identified August 16, 2026More mineral →

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Physical properties

Formation & geological history

Forms as a secondary mineral in arid, copper-rich weathering zones, usually replacing aluminum- and phosphate-bearing rocks. Deposits are commonly Cenozoic to younger, although turquoise can form over long weathering intervals.

Uses & applications

Used as a gemstone in cabochons, beads, carvings, and jewelry; lower-grade material is used decoratively and for lapidary specimens.

Geological facts

Its blue color comes mainly from copper, while greener hues reflect iron substitution or weathering. Famous sources include Iran, Arizona, Nevada, China, and Mexico.

Field identification & locations

Identify by its distinctive blue-green color, opaque appearance, moderate hardness, and often irregular brown or black matrix; a hardness or acetone test should be avoided on polished or treated pieces. The pictured tumbled cabochon appears turquoise or stabilized turquoise, but visual identification cannot confirm authenticity.