gemstone

Polished turquoise cabochon

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

AI-generated identification · may be incorrect

Opaque blue-green with dark matrix and a polished, waxy-to-subvitreous luster; Mohs hardness 5–6, specific gravity about 2.6–2.9. Turquoise is triclinic and has poor cleavage; the image does not reveal internal structure or allow reliable confirmation of natural versus treated material.

Identified September 25, 2026More gemstone →

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Physical properties

Formation & geological history

Forms secondarily when copper-rich waters alter aluminum- and phosphorus-bearing rocks, commonly in arid-zone oxidized deposits. Deposits range from ancient to geologically young; the specimen’s age and source cannot be determined from the photo.

Uses & applications

Used for cabochons, beads, and ornamental objects; lower-grade material is also used in inlay and crafts.

Geological facts

Its color comes mainly from copper, while iron can contribute green tones; dark veining may be host-rock matrix.

Field identification & locations

Look for opaque blue-to-green color, relatively low hardness, and possible matrix veining; major sources include Iran, the southwestern United States, China, and Mexico. Treatments and imitations are common, so testing or provenance is needed for authentication.