Mineral

Turquoise

Hydrated phosphate of copper and aluminium [CuAl6(PO4)4(OH)8·4H2O]

AI-generated identification · may be incorrect

Hardness: 5.0–6.0 on Mohs scale; Color: Sky blue, blue-green, or apple green; Luster: Waxy to subvitreous; Crystal Structure: Triclinic (rarely seen; usually cryptocrystalline/massive); Cleavage: Perfect (rarely observed); Specific Gravity: 2.6–2.9.

Hardness: 5
Color: Sky blue, blue-green, or apple green
Luster: Waxy to subvitreous

Identified January 23, 2026More mineral →

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Physical properties

Formation & geological history

Secondary mineral formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals (aluminum-rich rocks near copper deposits). Generally found in arid climates. Geological age varies but often associated with Tertiary formations.

Uses & applications

Primarily used as a gemstone in jewelry (cabochons, beads, and inlay) and for ornamental carvings. It has high value for collectors, especially specimens with unique matrix patterns or vibrant sky-blue 'Robin's Egg' coloration.

Geological facts

Turquoise is one of the oldest known gemstones; it was mined by Ancient Egyptians as early as 3000 BCE. Its name is derived from the French 'turquois', meaning 'Turkish', as it first reached Europe via Turkish trade routes.

Field identification & locations

Identify in the field by its characteristic waxy luster and blue-to-green hue, often found as veins or crusts in volcanic rocks or altered limestones. Common locations include Iran (Nishapur), Southwest USA (Arizona, Nevada), and China. Collectors should look for the 'matrix' (veins of host rock) which can help distinguish natural turquoise from synthetic or dyed imitations like howlite.

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Calcite–fluorite mineral specimen with iron-oxide staining

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Soil with Mineral Detritus and Quartz Fragments

Regolith / Silicate Mineral Aggregate

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Schist

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