mineral

Dioptase

Dioptase (CuSiO2(OH)2)

Hardness: 5 (Mohs scale); Color: Emerald-green to deep bluish-green; Luster: Vitreous (glassy); Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect; Specific Gravity: 3.28-3.35

Hardness: 5 (Mohs scale)
Color: Emerald-green to deep bluish-green
Luster: Vitreous (glassy)

Identified July 7, 2026More mineral →

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Physical properties

Hardness: 5 (Mohs scale); Color: Emerald-green to deep bluish-green; Luster: Vitreous (glassy); Crystal Structure: Trigonal/Rhombohedral; Cleavage: Perfect; Specific Gravity: 3.28-3.35

Formation & geological history

A secondary mineral that forms in the oxidation zones of copper deposits, typically in arid environments via the weathering of copper sulfides. Found in limestone or other carbonate rocks.

Uses & applications

Primarily valued as a collector's specimen due to its intense color and crystal habit. Occasionally used for small jewelry pieces, though its softness and cleavage make it fragile. Historically used as a pigment.

Geological facts

Dioptase crystals were first documented in the late 18th century in Kazakhstan and were initially mistaken for emeralds due to their vivid green color. It is often associated with other minerals like malachite, chrysocolla, and calcite.

Field identification & locations

Identify by its intense 'emerald' green color, rhombohedral crystal form, and relatively low hardness compared to true emerald. Common locations include the Tsumeb Mine in Namibia, Kazakhstan, and Arizona, USA.