Composition: (Fe3+,Fe2+,Zn)12(OH)6(AsO3)6[AsO3,SiO3(OH)]2
Crystal System : Hexagonal
Colours: Brownish-black
Lustre : Vitreous
Hardness (H) : 3
Year of Discovery: 1998
IMA Number: 1998-024
IMA Status: Approved
Discovered By: Michael Grieser (German collector)
Named for: Dieter Ekat (Namibian mining engineer)
References: Keller (2001)

Tsumeb is the Type Locality


Extremely rare. Reported to be from the "deep levels" of the mine, and believed to be from the second oxidation zone (?)


  • Supergene
  • 2nd Oxidation Zone

Paragenetic and General Notes

Ekatite is one of the rarer arsenite minerals discovered from Tsumeb. The original specimen was submitted for study by Michael Grieser, a German collector but, during the course of study, a second specimen was provided by Herbert Nägele, of Windhoek, Namibia, who was also the original source of the Grieser specimen. Ekatite occurs on a matrix of chalcocite and quartz, as small radiating sprays of striated brownish-black needles. Ekatite is structurally related to phosphoellenbergerite, ellenbergerite and holtedahlite, as well as to several transition-metal tellurites, selenites and phosphites.