Cuprite

Cuprite


Composition: Cu2O
Crystal System : Cubic
Colours: Dark-red, cochineal-red, reddish-grey, grey-black
Lustre : Adamantine, sub-metallic, earthy
Hardness (H) : 3.5-4.0
Specific Gravity (S.G) : 6.14

Distribution

Common. First, second and third oxidation zones.

Occurrence

  • Supergene
  • 1st Oxidation Zone
  • 2nd Oxidation Zone
  • 3rd Oxidation Zone

Notable Finds

Spectacular examples of cuprite (v. chalcotrichite) were found on 12 Level, towards the base of the first oxidation zone (ref. Wilhelm Klein collection # 807; Harvard University # 126820). Von Bezing et al. (2014) also note chalcotrichite with copper and calcite from the second oxidation zone. In the third oxidation zone, on 44 Level, cuprite crystals to 50 mm were found.

Paragenetic and General Notes

Most commonly as octahedral modifications on cubic and dodecahedral crystals; unmodified cubes and octahedra are rare (Von Bezing et al., 2014).

Fine examples of acicular cuprite (var. chalcotrichite) occur in association with calcite and dolomite.  Inclusions of chalcotrichite in calcite and in cerussite are the cause of intense orange and / or red colouration in those minerals.

Cuprite is reported to form pseudomorphs after the following minerals:  copper (common).

The following minerals are reported to form pseudomorphs after cuprite:  conichalcite (rare); malachite (common, though often partial); plancheite (rare).