mineral
Polished turquoise cabochon pendant
Turquoise, hydrated copper–aluminum phosphate: CuAl₆(PO₄)₄(OH)₈·4H₂O
AI-generated identification · may be incorrectOpaque blue-green, waxy to subvitreous luster, commonly brown or black limonite matrix; Mohs hardness 5–6, triclinic structure, no prominent cleavage, specific gravity about 2.6–2.9. The pictured stone is polished and mounted in metal.
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Physical properties
Opaque blue-green, waxy to subvitreous luster, commonly brown or black limonite matrix; Mohs hardness 5–6, triclinic structure, no prominent cleavage, specific gravity about 2.6–2.9. The pictured stone is polished and mounted in metal.
Formation & geological history
Forms as a secondary mineral in arid, copper-rich, phosphate-bearing rocks through groundwater alteration, commonly during Cenozoic weathering. Major deposits occur in Iran, the southwestern United States, China, Chile, and Mexico.
Uses & applications
Used for cabochons, beads, inlay, carvings, and ornamental jewelry; historically valued as a decorative and symbolic stone. It has little industrial use.
Geological facts
Color ranges from sky blue to green depending largely on copper, iron, and zinc content; matrix patterns can help indicate locality. Much commercial turquoise is stabilized with resin, reconstituted, dyed, or simulated.
Field identification & locations
Identify by its opaque blue-green color, relatively soft feel, waxy polish, and natural matrix; glassy translucence or extreme hardness suggests an imitation. Common localities include Arizona, Nevada, New Mexico, Iran, and Hubei, China.
