gemstone

Turquoise (likely polished nugget)

Turquoise, CuAl₆(PO₄)₄(OH)₈·4H₂O

AI-generated identification · may be incorrect

Opaque sky-blue to blue-green with dark matrix veining; waxy to subvitreous luster, triclinic crystal structure, Mohs hardness 5–6, specific gravity about 2.6–2.9. The photo’s color and shape suggest turquoise, though visual identification is not definitive.

Identified October 8, 2026More gemstone →

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Physical properties

Formation & geological history

A hydrated copper-aluminum phosphate formed during near-surface weathering of copper deposits, commonly in arid regions. Deposits range from relatively young to ancient; the specimen’s age cannot be determined from the image.

Uses & applications

Cut and polished into jewelry and ornamental objects; also collected as a gemstone.

Geological facts

Natural turquoise often contains brown or black host-rock matrix; some vivid turquoise-colored material is dyed or otherwise treated.

Field identification & locations

Look for opaque blue-green color, matrix patterns, and a relatively soft feel; common sources include Iran, the southwestern United States, China, and Mexico. The image alone cannot confirm natural turquoise or distinguish it from imitation.