Berthierine

Berthierine has been reported from Tsumeb on a specimen in the collection of Walter Veldsman (https://www.mindat.org/photo-1169313.html; accessed April 2023). The berthierine was identified by Joy Désor using a combination of SEM-EDS and PXRD and the reported paragenesis, which includes leiteite and ludlockite, is strongly supportive of the specimen’s Tsumeb origin.

The berthierine occurs as minute radiating sprays which, based on the SEM image, appear to consist of elongated, spindle-shaped crystals to c. 30 µm in length. Unfortunately, a detailed description of the material was not provided.

The limited description also lists tennantite-(Fe) as an associated mineral but offers no indication as to how this species was identified. There is no record of tennantite-(Fe) from Tsumeb in the peer-reviewed literature and neither is it listed on Mindat (as of December 2023).