gemstone

Turquoise

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

AI-generated identification · may be incorrect

Mohs hardness 5–6; blue to blue-green, commonly with brown or black matrix. It has a waxy to subvitreous luster, cryptocrystalline structure, and no prominent cleavage; the pieces shown are polished and drilled beads.

Identified August 19, 2026More gemstone →

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Physical properties

Formation & geological history

Turquoise forms as a secondary mineral in arid climates through groundwater alteration of aluminum- and copper-bearing rocks, commonly in veins and nodules. Deposits are geologically young to ancient, with major occurrences associated with Cenozoic weathering zones.

Uses & applications

Used for beads, cabochons, inlay, and ornamental jewelry; lesser material is used decoratively. It is also an important traditional gemstone in many cultures.

Geological facts

The vivid blue color comes mainly from copper, while iron commonly shifts it toward green. Much commercial turquoise is stabilized with resin, reconstituted, dyed, or treated to improve durability and color.

Field identification & locations

Identify it by its opaque blue-green color, relatively low hardness, porous/waxy surface, and occasional host-rock matrix; glass and dyed howlite are common imitations. Major sources include Iran, Arizona and Nevada, China, Mexico, and Egypt.