biehlite

The biehlite type material is believed to have been collected as early as 1989, from an undisclosed location in the mine and by an anonymous miner. According to Schlüter et al. (2000) it probably originated from "… between level 42 and 48" (i.e., from the third oxidation zone). At the time of discovery the fibrous nature of the mineral precluded the collection of sufficient structural data to meet the IMA guidelines for acceptance of a new mineral. A later re-examination, however, resulted in the approval of IMA 1999-019a which was named biehlite in honour of Dr Friedrich Karl Biehl, a pioneer of early mineralogical research on Tsumeb. The crystal structure was refined by Adiwidjaja et al. (2000). Type material is conserved at the Mineralogisches Museum, Universität Hamburg, Germany (catalogue number MMHH TS220).

Biehlite is notable for its composition given that antimony is a scarce element at Tsumeb. It presents as irregular aggregates and felty masses of white fibres typically to 10 mm in length, exceptionally to 35 mm, but only a few µm in diameter. The fibres are translucent with a silky lustre, soft and flexible. Biehlite is typically associated with anglesite and sometimes with wulfenite, on fine-grained, copper-rich massive sulphide ore.

anglesite; wulfenite