mineral

Tumbled turquoise

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

AI-generated identification · may be incorrect

Opaque sky-blue to blue-green, waxy to subvitreous luster, typically cryptocrystalline and commonly patterned with dark matrix; Mohs hardness 5–6, specific gravity about 2.6–2.9, with no prominent cleavage. The rounded shape indicates tumbling and polishing;…

Identified August 28, 2026More mineral →

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Physical properties

Formation & geological history

Forms as a secondary phosphate mineral in arid, oxidized zones of copper deposits, generally during weathering of older host rocks; individual deposits range from Precambrian to recent geologic age.

Uses & applications

Used for cabochons, beads, inlay, carvings, and jewelry; lower-grade material is also used decoratively. It has little industrial use.

Geological facts

Major sources include Iran, the American Southwest, China, Egypt, Chile, and Mexico. A scratch test is best avoided on a finished piece; turquoise is porous and is often stabilized with resin or treated with dye.

Field identification & locations

Identify by its blue-green color, relatively low hardness, waxy surface, low density, and occasional brown or black limonite matrix. Confirm with gemological testing because dyed howlite, magnesite, and plastic imitations are common.