mineral

Turquoise (likely Stabilized or Dyed Howlite/Magnesite)

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

Hardness: 5-6 (Mohs scale), Color: Sky blue to blue-green, Luster: Waxy to subvitreous, Crystal structure: Triclinic (usually cryptocrystalline), Cleavage: None (conchoidal fracture), Specific Gravity: 2.6-2.9

Identified March 8, 2026More mineral →

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Physical properties

Formation & geological history

Formed by the percolation of acidic aqueous solutions during the weathering and oxidation of pre-existing minerals. It is usually found in arid regions, filling veins or as nodules in volcanic rocks or sedimentary phosphate-rich rocks.

Uses & applications

Primarily used in jewelry for cabochons, beads, and inlays. Historically valued as an ornamental stone and amulet for thousands of years.

Geological facts

Turquoise is one of the oldest known gemstones, used by the ancient Egyptians as early as 3000 BCE. The name comes from the French 'turquois' meaning 'Turkish', as it first reached Europe via Turkey from Persian mines.

Field identification & locations

Identify by its unique 'robin's egg' blue color and waxy appearance. In the field, look for it in arid climates near copper deposits. For collectors, beware of 'Howlite' dyed to look like turquoise; genuine turquoise is cool to the touch and does not lose color when rubbed with acetone.

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Sandstone (with potential mineral staining/concretions)

Arenite (SiO2 based)

sedimentary

Epidote

Epidote | Ca2(Al2,Fe3+)(SiO4)(Si2O7)O(OH)

metamorphic

Nephrite Jade

Nephrite

Mineral/Rock

Banded Gneiss (River Rock/Pebble)

Gneiss (specifically a banded variety often found as a river rock)

Metamorphic Rock

Green Apatite on Albite

Fluorapatite [Ca5(PO4)3F] on Albite [Na(AlSi3O8)]

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Epidote

Epidote - Ca2(Al2,Fe3+)3(SiO4)3(OH)

mineral