vanadinite

Vanadinite is a relatively common mineral in the Otavi Mountainland, with fine examples recorded from localities such as Abenab, Abenab West, Berg Aukas and Okarundu (Cairncross 1997). Nevertheless, vanadinite is an extremely rare mineral at Tsumeb. Vanadinite specimens from other Namibian localities have sometimes been mis-attributed to Tsumeb, and "Tsumeb" vanadinites should be regarded with caution.

Klein (1938) described vanadinite (and descloizite) as very rare at Tsumeb, occurring between surface and 6 Level.

Strunz et al. (1958) listed vanadinite as a rare mineral in the first oxidation zone but it is absent from their listing of second oxidation zone minerals. However, Geier (1973/4) later observed vanadinite in the cores of descloizite aggregates from the second oxidation zone but described both minerals as "extremely rare".

Lombaard et al. (1986) noted that vanadium mineralisation at Tsumeb (chiefly as mottramite) is concentrated at the top of the first oxidation zone (between surface and 4 Level), and that there is a similar concentration at the top of the second oxidation zone. Gebhard (1999) is in broad agreement, stating that vanadium mineralisation was restricted, essentially, to an interval between 50 m and 100 m below surface, and that brown crystals of vanadinite were found, very rarely, in that zone.

Pinch and Wilson (1977) indicated that vanadinite "… forms brownish red prismatic crystals to several mm" but this has not been substantiated and the description may refer to hematite-stained mimetite crystals that occurred, albeit rarely, in the first oxidation zone.

Weber (1977) described vanadinite from Tsumeb as "very rare" but listed vanadinite after pyromorphite as an observed Tsumeb pseudomorph, along with a Smithsonian Institution catalogue number (B13415). Weber’s interpretation of this specimen is questionable and merits further investigation.

Bowell and Mocke (2018) reported the presence of vanadinite with descloizite "… in zoned alteration bands" in a specimen attributed to 34 Level in the second oxidation zone. The specimen is part of the Söhnge Collection at the Geological Survey of Namibia.

A specimen of smithsonite with inclusions of vanadinite (allegedly EDS confirmed) was in the collection of the late Jim Robison (1941-2018).

descloizite; mottramite; smithsonite; tangeite (?)

Vanadinite has been reported to form pseudomorphs after the following minerals: pyromorphite (rare, doubtful status).