mineral
Polished turquoise (likely stabilized)
Turquoise — hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
AI-generated identification · may be incorrectTypically blue-green to green with dark matrix; waxy to subvitreous luster, cryptocrystalline structure, no visible cleavage, Mohs hardness 5–6, specific gravity about 2.6–2.8. The rounded, glossy surface suggests a polished or tumbled specimen; exact identification is uncertain from the image alone.
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Physical properties
Typically blue-green to green with dark matrix; waxy to subvitreous luster, cryptocrystalline structure, no visible cleavage, Mohs hardness 5–6, specific gravity about 2.6–2.8. The rounded, glossy surface suggests a polished or tumbled specimen; exact identification is uncertain from the image alone.
Formation & geological history
Forms as a secondary mineral in arid, copper-rich, phosphate-bearing rocks through groundwater alteration, commonly in Cenozoic weathering zones. Major sources include Iran, the southwestern United States, China, Chile, and Mexico.
Uses & applications
Used for cabochon jewelry, beads, carvings, and ornamental objects; historically important in Indigenous and Persian jewelry traditions. Lower-grade material is often stabilized with resin to improve durability.
Geological facts
Natural turquoise commonly shows brown, black, or reddish host-rock matrix, while color ranges from sky blue to green depending partly on iron and copper content. It is porous and can darken or absorb oils during handling.
Field identification & locations
Field clues include blue-green color, opaque appearance, relatively low hardness, and a waxy polish; it should not scratch glass reliably. Similar materials include dyed howlite, magnesite, chrysocolla, and turquoise composite, so laboratory testing may be required.
