mineral

Turquoise (Rough Specimens)

Hydrous phosphate of copper and aluminium - CuAl6(PO4)4(OH)8·4H2O

Hardness: 5-6 (Mohs scale). Color: Sky blue to blue-green to apple green. Luster: Waxy to subvitreous. Crystal Structure: Triclinic (usually massive or cryptocrystalline). Cleavage: Perfect (rarely seen). Specific Gravity: 2.6-2.9.

Hardness: 5-6 (Mohs scale)
Color: Sky blue to blue-green to apple green
Luster: Waxy to subvitreous

Identified February 11, 2026More mineral →

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Physical properties

Formation & geological history

Formed as a secondary mineral by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. Typically found in arid regions within volcanic rocks or altered sedimentary phosphate-rich rocks.

Uses & applications

Primary use is in jewelry and lapidary arts as gemstones or cabochons. Massive pieces are values as ornamental stones and by mineral collectors. It has significant cultural value in Southwestern US and Persian arts.

Geological facts

The specimen in the image is specifically referred to as 'Morenci and Blue Diamond' turquoise, known for its high-quality matrix and deep blue tones. It is one of the first gemstones ever mined, dating back to 3000 BCE in Ancient Egypt.

Field identification & locations

Identify in the field by its distinct robin-egg blue color and association with copper deposits (limonite or pyrite matrix). Common locations include Arizona and Nevada (USA), Iran, and China. Collectors look for 'spiderweb' matrix patterns.

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