Composition: Pb2+4(S6+O3S2-)O2(OH)2
Crystal System : Triclinic
Colours: Colourless, beige-cream
Lustre : Vitreous, earthy
Hardness (H) : 1-2
Specific Gravity (S.G) : 6.77
IMA Number: 1998-036
IMA Status: Approved
Discovered By: Charles Key (American dealer)
Named for: Sidney Pieters (Namibian dealer)
References: Roberts et al. (1999)

Tsumeb is the Type Locality


Extremely rare. Third oxidation zone.


  • Supergene
  • 3rd Oxidation Zone

Notable Finds

The type specimen is from the third oxidation zone, between 40 and 44 levels.

Paragenetic and General Notes

Sidpietersite was the first thiosulphate mineral identified at Tsumeb. It occurs as warty, nodular masses, and as free-standing, radiating aggregates of colourless, to cream-coloured, bladed crystals to 3 mm.

Roberts et al. (1999) considered sidpietersite to have formed as an intermediate step in the oxidation of galena. It occurs both on the galena / sphalerite matrix and on zincite-coated smithsonite crystals on the type specimen. Minor quartz and greenockite are associated.