Composition: ZnAl2(AsO4)(OH)5
Crystal System : Triclinic
Colours: Brown, yellowish-brown, dark-brown
Lustre : Adamantine
Year of Discovery: 1983
IMA Number: 1983-049a
IMA Status: Approved
Named for: Gerd Tremmel (German mineralogist)

Tsumeb is the Type Locality


Extremely rare. Second oxidation zone (type specimen), and third oxidation zone.


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

Paragenetic and General Notes

A member of the tsumcorite group, described from the second oxidation zone with powellite; betpakdalite; scorodite; hematite; kaolinite; quartz. A second occurrence was found in the third oxidation zone with wilhelmkleinite, adamite and Al-rich scorodite.