Image Credit: RRUFF Database Project (Lafuente et al. 2015; RRUFF ID 070114)
Mineral Species
Bartelkeite
Type Locality
Yes
Composition
PbFe2+Ge6+(Ge4+2O7)(OH)2·H2O
Crystal System
Monoclinic
Status at Tsumeb
Confirmed (type locality)
Abundance
Extremely rare
Distribution
Second oxidation zone
Paragenesis
Supergene
Entry Number
Species; TSNB40
Type Mineralogy
The discovery of bartelkeite, IMA 1979-029, is credited to Dr Wolfgang Bartelke for whom the mineral is named (Keller et al. 1981a). The level of the mine from which the type specimen originated is not recorded but it is almost certainly from the second oxidation zone. Co-type specimens are conserved at the Smithsonian Institution (catalogue number NMNH 148302) and at the Institut für Mineralogie und Kristallchemie, Universität Stuttgart, Germany (NM 07).
General Notes
Bartelkeite is an inconspicuous, yet distinctive, mineral occurring typically in shallow vugs in partly oxidised germanium-rich sulphide ores, comprising germanite, tennantite, renierite and galena. It presents as colourless to pale green crystals, < 1 mm in size, tabular to acicular, but with highly characteristic notches. The original description (Keller et al. 1981a; Keller and Bartelke, 1982) gave the formula as PbFeGe3O8. The structure and a revised formula were determined by Origlieri et al. (2012).
Specimens of bartelkeite in association with a "…Ge-rich segnitite as pseudo-cubic crystals" and an "…unknown Fe3+Ge1+ oxide" were offered for sale by Joy Désor (ex. Armin Schöler) in December 2022. All mineral phases had been verified by SEM-EDS.
Associated Minerals
fleischerite; galena; germanite; plumbogummite; renierite; segnitite; söhngeite; tennantite-(Zn)
