Andyrobertsite, with calcioandyrobertsite


Composition: KCaCu5(AsO4)4[As(OH)2O2].2H2O
Crystal System : Orthorhombic; Monoclinic
Lustre : Vitreous
Hardness : 3
Specific Gravity : 4.01
Year of Discovery: 1996
IMA Number: 1997-023
IMA Status: Approved
Discovered By: W.W. (Bill) Pinch (American collector)
Named for: Composition/relationship (to andyrobertsite)
References: Cooper et al. (1999)


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

Notable Finds

The type-specimen (W.Pinch collection, probably from the first oxidation zone) has attained iconic status. Subsequently, microcrystalline mixtures of calcioandyrobertsite and stranskiite have been found filling fractures in tennantite-rich massive sulphide ores fro the third oxidation zone.