Rock Identifier
Blue-green turquoise (probable) (Turquoise, hydrous copper aluminum phosphate — CuAl₆(PO₄)₄(OH)₈·4H₂O) — mineral
mineral

Blue-green turquoise (probable)

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

AI-generated identification · may be incorrect

Opaque blue to blue-green, typically waxy to dull luster; Mohs hardness 5–6, cryptocrystalline aggregate, no obvious cleavage, and specific gravity about 2.6–2.8. The small rounded piece may be polished or tumbled; image-based identification is not definitive.

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Physical properties

Opaque blue to blue-green, typically waxy to dull luster; Mohs hardness 5–6, cryptocrystalline aggregate, no obvious cleavage, and specific gravity about 2.6–2.8. The small rounded piece may be polished or tumbled; image-based identification is not definitive.

Formation & geological history

Forms as a secondary mineral in arid, copper-rich, phosphate-bearing weathering zones, commonly replacing host rock near copper deposits. Deposits range from tens to hundreds of millions of years old depending on locality.

Uses & applications

Used as a gemstone, cabochon, bead, and ornamental material; historically important in jewelry and religious objects. Stabilized or dyed turquoise is common commercially.

Geological facts

Natural turquoise often contains brown or black limonite/matrix veining, though some varieties are nearly uniform blue. Similar-looking materials include chrysocolla, dyed howlite, variscite, and synthetic turquoise.

Field identification & locations

Check for opaque blue-green color, waxy texture, moderate hardness, and a warm, nonmetallic appearance; avoid relying on color alone. Major sources include Iran, the southwestern United States, China, Egypt, and Mexico.