gemstone

Turquoise

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

AI-generated identification · may be incorrect

Opaque blue-green, with dark matrix veining; waxy to dull luster and typically massive, without visible crystals. Mohs hardness is about 5–6; specific gravity about 2.6–2.9.

Identified September 26, 2026More gemstone →

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Physical properties

Opaque blue-green, with dark matrix veining; waxy to dull luster and typically massive, without visible crystals. Mohs hardness is about 5–6; specific gravity about 2.6–2.9.

Formation & geological history

Forms when copper-bearing fluids alter aluminum- and phosphate-rich rocks, commonly in arid-zone deposits. Deposits range from ancient to geologically recent; the specimen’s age and locality cannot be determined from the image.

Uses & applications

Used for cabochons, beads, and decorative objects; historically valued in jewelry and ornament. Lower-grade material may be stabilized or treated for durability.

Geological facts

Turquoise is a hydrated phosphate mineral, not a rock type; its blue-green color comes chiefly from copper, while iron can contribute greener tones.

Field identification & locations

Likely turquoise, though the small, polished-looking piece cannot be confirmed visually; look for opaque color, waxy luster, and natural matrix, and verify with gemological testing. Notable sources include the southwestern United States, Iran, China, and Egypt.