Dioptase
Image: Deidre Woollard (CC BY 2.0)
Mineral NameDioptase
Chemical FormulaCuSiO3·H2O
Mohs Hardness5
Crystal Systemtrigonal
Lustervitreous
Streak ColorGreen
CleavagePerfect on {1011}
FractureConchoidal to uneven
Specific Gravity3.28
Colorsemerald-green, bluish-green
TransparencyTransparent to translucent
Type LocalityTsumeb, Namibia
Mineral GroupCyclosilicates
Usescollector, jewelry
Associated Mineralscalcite, chrysocolla, malachite, azurite, quartz
Rarityuncommon
Description
Dioptase is a striking emerald-green to bluish-green cyclosilicate mineral, often forming beautiful, well-developed prismatic to rhombohedral crystals.
Geological Context
It is a secondary mineral found in the oxidized zones of copper sulfide deposits, typically in arid climates, forming from the alteration of primary copper minerals.
