Brunogeierite Field of view: 600 μm Locality: Tsumeb Mine (Ongopolo Mine), Tsumeb, Oshikoto Region, Namibia Description: Shiny brunogeierite xls between larger chalcosite (not in picture; as is stottite, which why it was checked by SEM-EDS) covered with a delicate greenish-yellowish crystalline layer with detected Ge and Fe only. Maybe eyselite or related? — Photo: Franz Neuhold (formerly Breier) · Public domain
Brunogeierite
Brunogeierite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Fe²⁺₂Ge⁴⁺O₄.
It crystallizes in the cubic crystal system (space group Fd3m). It is a member of the Spinel structural group.
Key properties: Mohs hardness 5; specific gravity 5.51.
IMA symbol Bng, IMA status: approved, named in 1972.
Found in the lower oxidation zone of a dolostone-hosted hydrothermal polymetallic ore deposit, at a depth of 930 meters (Tsumeb, Namibia).
It is found associated with Tennantite, reniérite, zincian stottite (Tsumeb, Namibia); sphalerite, magnetite (France).
The name refers to Dr. Bruno H. Geier (1902–1987), formerly Chief Mineralogist, Tsumeb Corporation, Tsumeb, Namibia.