
mineral
Tumbled turquoise
Turquoise, hydrated copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O
AI-generated identification · may be incorrectOpaque blue-green color with dark brown/black matrix and waxy-to-subvitreous luster; typically cryptocrystalline and massive, with no visible cleavage. Mohs hardness 5–6; specific gravity about 2.6–2.8.
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Physical properties
Opaque blue-green color with dark brown/black matrix and waxy-to-subvitreous luster; typically cryptocrystalline and massive, with no visible cleavage. Mohs hardness 5–6; specific gravity about 2.6–2.8.
Formation & geological history
Forms as a secondary mineral in arid, oxidized zones of copper deposits, often replacing aluminous or phosphate-bearing rock. Most specimens are Cenozoic to younger, though turquoise deposits occur in much older host rocks.
Uses & applications
Used as a gemstone in cabochons, beads, carvings, and jewelry; also valued as a decorative collector material. This appears polished and tumbled rather than natural crystal-form.
Geological facts
The dark web-like pattern is turquoise matrix, commonly iron or manganese-stained host rock; uniform blue material is generally more valuable than heavily matrixed material.
Field identification & locations
Identify by its opaque sky-blue to green color, black/brown matrix, relatively low hardness, and nonmetallic waxy surface; common sources include Iran, Arizona, Nevada, China, and Mexico. Avoid prolonged soaking, chemicals, heat, and oils.