Tsumcorite

Tsumcorite


Composition: Pb(Zn,Fe3+)2(AsO4)2(H2O,OH)2
Crystal System : Monoclinic
Colours: Yellow, yellow-brown, red-brown, orange
Lustre : Vitreous (crystals). Earthy (massive)
Hardness (H) : 4.5
Specific Gravity (S.G) : 5.2
Year of Discovery: 1969
IMA Number: 1969-047
IMA Status: Approved
Discovered By: Bruno H. Geier (Tsumeb mineralogist)
Named for: The Tsumeb Corporation
References: Geier et al. (1971)

Tsumeb is the Type Locality

Distribution

Rare. Occurs in all three oxidation zones.

Occurrence

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

Notable Finds

The type specimen is from the second oxidation zone, but tsumcorite was subsequently recognised on first oxidation zone material that had been mined in the 1920s. Good examples of tsumcorite were encountered between 28 and 30 levels, and the best find was arguably from 30 Level, where bright yellow crystals to 5 mm are perched on red-brown iron oxides (Gebhard, 1999).

Paragenetic and General Notes

On the type specimen, tsumcorite occurs with beudantite, anglesite, mimetite, and "other arsenates", as prismatic, wedge-shaped crystals, exceptionally to 5 mm, arranged in sheaves or spherulites.

Tsumcorite also occurs as feathery, powdery aggregates and crusts.

Pinch and Wilson (1977) report attractive combinations with pale-green willemite, apple-green smithsonite, or yellow mimetite.