scheelite

Scheelite is the rarest of the scheelite group minerals occurring at Tsumeb (the others being powellite, stolzite and wulfenite). Gebhard (1991) reported only a single occurrence of scheelite from Tsumeb, as atypical microcrystalline sheets of nacreous, honey-colored material associated with stolzite.

However, a more significant discovery of scheelite was made in 1994 on 46 level (Gebhard 1999), deep in the third oxidation zone, where a small pocket yielded an unusual paragenesis comprising well-crystallized chalcocite, fraipontite, quartz, scheelite, siderite and stolzite. The scheelite occurs as golden-brown, pseudo-octahedral crystals, to a few millimetres in size, closely resembling stottite, for which it was originally mistaken.

Scheelite forms a series with powellite (CaMoO₄), and crystals of intermediate composition (c. 60% scheelite : 40% powellite) have been analysed from a specimen in the Feinglos Collection (now at Harvard University, MGMH 2022.4.7770L). The golden-brown, pseudo-octahedral crystals of scheelite on this specimen reach a few mm in size and are associated with quartz and fraipontite, on a sulphide matrix (Mark Feinglos, pers. comm. to M. Southwood, September, 2015).

chalcocite; fraipontite; quartz; siderite; stolzite