Conichalcite

Conichalcite


Composition: CaCu2+(AsO4)(OH)
Crystal System : Orthorhombic
Colours: Grass-green, bright-green, dirty-green.
Lustre : Sub-vitreous, greasy, earthy
Hardness (H) : 4.5
Specific Gravity (S.G) : 4.33
References: Gebhard (1999)

Distribution

Common. First, second, and third oxidation zones.

Occurrence

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

Notable Finds

On 43 Level, as deep-grass-green crystals to 2mm.

Paragenetic and General Notes

Common as globular aggregates to c. 3 mm, or as crusts or irregular masses. Rarely as crystals, although the 43 Level find provides a notable occurrence in this regard, and Von Bezing et al. (2014) report that prismatic crystals to 3 mm have also been found. Conichalcite forms a series with duftite and these two minerals are readily confused. Analytical verification is usually required to differentiate these two minerals with confidence.

On 43 Level, in the third oxidation zone, conichalcite occurred in an unusual paragenesis with calcite, cuprite, and silver-amalgam (Gebhard, 1999).

Conichalcite is reported to form pseudomorphs after the following minerals:  calcite (rare); chalcocite (rare); cuprite (rare) wulfenite (rare).