germanocolusite

Geier and Ottemann (1970a,b) analysed "germanite" samples from Tsumeb by EMPA and identified several compositional varieties including one enriched in vanadium and arsenic. More than 20 years later, germanocolusite was described as a new mineral by Spiridonov et al. (1992) with a composition that almost certainly corresponds to the vanadium-enriched germanite that was mis-interpreted by Geier and Ottemann (1970b).

The description of germanocolusite provided by Spiridonov et al. (1992) is based on specimens from Urup (in Russia), Maikain (in Kazakhstan), Chelopech (in Bulgaria) and Tsumeb, all of which are included in the IMA mineral list thereby implying shared type locality status (http://cnmnc.units.it/; accessed January 2023). However, the conserved type material at the Fersman Mineralogical Museum, Moscow, and the Mineralogical Museum of St Petersburg is from the Russian locality and according to Mindat, type locality status is shared between Urup (Russia) and Maykain (Kazakhstan) (Germanocolusite: Mineral information, data and localities. (mindat.org) ; accessed December 2022).

While there are very slight differences in the optical properties of germanite group minerals, germanocolusite requires a compositional analysis for certain identification. It is only observable under the ore microscope or with electron beam techniques.

According to Spiridonov et al. (1992) germanocolusite at Tsumeb occurs in tennantite, sphalerite and chalcopyrite ore with germanite, gallite, chalcocite, enargite, and bornite.

bornite; chalcocite; chalcopyrite; enargite; fluorapatite; gallite; germanite; maikainite; ovamboite; sphalerite; tennantite-(Zn); titanite