molybdenite

Molybdenite is widely but very sparsely distributed at Tsumeb, mainly in sulphide ores and typically only as microscopic inclusions in other sulphide minerals. It occurs only in trace quantities, however, and as such is considered a very rare mineral (Lombaard et al. 1986; Hughes 1987; Gebhard 1999). Molybdenite is readily confused with tungstenite under the ore microscope and it is notable that both of these minerals occur in similar parageneses at Tsumeb.

Kriesel (1924) analysed the newly discovered mineral germanite and found that it contained 0.03 wt % molybdenum. This does not appear to have been linked to the presence of molybdenite inclusions at that time; Moritz (1933) makes no mention of molybdenite in his study of sulphide ores between surface and 16 Level.

Strunz et al. (1958a) mentioned the occurrence of molybdenite as tiny, microscopic particles in the primary sulphide ore.

Geier and Ottemann (1970b) noted minute inclusions of molybdenite in certain Mo-enriched germanite. Geier and Ottemann (1971a) described molybdenite intergrown with tungstenite in crypto-crystalline bands.

Bartelke (1976) suggested that minute inclusions of molybdenite accounted for the molybdenum content of germanite reported by Kriesel (1924). He also recorded a specimen with a 5 mm crystal of molybdenite associated with stottite and schneiderhöhnite.

Pinch and Wilson (1977) indicated that a specimen with a 30 mm hexagonal, pyramidal crystal, with stottite and schneiderhöhnite is known, but this seems questionable and was possibly a misinterpretation of Bartelke's observation.

Hughes (1987) described the association of molybdenite (in trace amounts) in a complex sulphide paragenesis commonly hosted by dark dolostone breccia. The association includes bornite, chalcopyrite, galena, gallite, germanite, pyrite, renierite, sphalerite, sulvanite and tennantite.

Aggregates (to c. 3 mm) of minute crystals of molybdenite have been reported in association with cerussite and minor anglesite by Joy Désor (https://www.mindat.org/photo-1063403.html; accessed November 2022). It seems probable that these aggregates are relict hypogene sulphide (rather than molybdenite of supergene origin).

anglesite; bornite; cerussite; chalcopyrite; galena; gallite; germanite; maikainite; ovamboite; pyrite; pyromorphite; renierite; schneiderhöhnite; sphalerite; stottite; sulvanite; tennantite-(Zn); tungstenite