Dioptase on Calcite


Composition: Cu6Si6O18.6H2O
Crystal System : Trigonal
Lustre : Vireous, sub-adamantine
Hardness : 5
Specific Gravity : 3.28-3.35
References: Cook (2002a)


  • Supergene
  • 2nd Oxidation Zone
  • 3rd Oxidation Zone

Notable Finds

30 Level: ".... miners encountered numerous pockets, some very large, that contained thousands of specimens of breathtakingly beautiful, dark emerald-green dioptase." (Key, 1996). 32 Level, Zero Stope: Some of the best dioptase on contrasting white calcite matrix (Clive King, 2014, private communication to M.Southwood). 33 Level: Dioptase supplanted by gemmy crystals of cerussite, both on white calcite, discovered in 1975 (Key, 1977). In the third oxidation zone, on 44 Level, with malachite and conichalcite (Gebhard, 1999). Also in the third oxidation zone with wulfenite (Gebhard, op.cit.).