mineral
Turquoise
Hydrated copper aluminum phosphate, CuAl₆(PO₄)₄(OH)₈·4H₂O
AI-generated identification · may be incorrectTypically opaque sky-blue to green, with a waxy to subvitreous luster and hardness of 5–6 Mohs. It is cryptocrystalline, lacks visible cleavage, and commonly contains brown or black matrix, as shown here.
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Physical properties
Typically opaque sky-blue to green, with a waxy to subvitreous luster and hardness of 5–6 Mohs. It is cryptocrystalline, lacks visible cleavage, and commonly contains brown or black matrix, as shown here.
Formation & geological history
Forms as a secondary mineral in arid, copper-rich zones where phosphate-bearing groundwater alters aluminum minerals. Most gem turquoise formed relatively recently in geologic terms, commonly within Cenozoic weathering environments.
Uses & applications
Used as a cabochon gemstone, beads, carvings, and ornamental inlay; historically important in jewelry and ceremonial objects. It is generally too soft and porous for heavy industrial or construction use.
Geological facts
The blue color comes mainly from copper, while iron commonly shifts it toward green. Stabilization, dyeing, or resin treatment is common in commercial turquoise and can significantly affect value.
Field identification & locations
Identify it by its opaque blue-green color, low-to-moderate hardness, waxy surface, and irregular matrix; it should not fizz in dilute acid. Major sources include Iran, southwestern United States, China, Chile, and Mexico.
