Dioptase
Image: cobalt123 from Phoenix, Arizona, USA (CC BY-SA 2.0)
Mineral NameDioptase
Chemical FormulaCuSiO3·H2O
Mohs Hardness5
Crystal Systemtrigonal
Lustervitreous
Streak Colorgreen
Cleavageperfect on {1011}
Fractureconchoidal
Specific Gravity3.28
Colorsemerald green, bluish-green, dark green
Transparencytransparent
Type LocalityTsumeb, Namibia
Mineral Groupsilicates
Usescollector's mineral, minor gemstone
Associated Mineralsmalachite, chrysocolla, calcite, quartz, azurite
Rarityuncommon
Description
This specimen features a vibrant cluster of deep emerald green, transparent to translucent dioptase crystals, exhibiting a 'gemmy' quality and forming a significant mass on its matrix.
Geological Context
Dioptase is a secondary copper cyclosilicate mineral that forms in the oxidized zones of copper sulfide deposits, typically in arid or semi-arid environments.
