tsumcorite (w. duftite)

A rich botryoidal crust of mustard-yellow to orange tsumcorite, lining a vug in partly oxidised sulphide ore with brown goethite; smaller vugs containing dark-green crystals of duftite and saccharoidal crusts of off-white dolomite are also present.

Mark Feinglos obtained this specimen from Georg Gebhard, whose label records that it was collected by Tsumeb Corporation mineralogist Bruno Geier in 1964 from an unusual arsenate paragenesis at East 49 on 30 Level, in the second oxidation zone. Tsumcorite (Geier et al. 1971) and jamesite (Keller et al. 1981b) were subsequently described from this discovery. Gebhard's label also indicates that carminite and jamesite are present on the specimen but these minerals have not been verified.

It appears that Geier conserved a considerable amount of material from this discovery from which numerous specimens have been dispersed, labelled as "part of type specimen" for either tsumcorite or jamesite.

dolomite; duftite; goethite