beaverite-(cu)

Beaverite-(Cu), formerly "beaverite", was renamed as part of a series of nomenclature recommendations for the alunite supergroup (Bayliss et al. 2010).

It is noted that a Zn-rich beaverite from the Mikawa mine, Niigata Prefecture, Japan, was described by Sato et al. (2008) and subsequently approved as a new mineral species, beaverite-(Zn), IMA 2010-086 (Sato et al. 2011). Beaverite-(Zn), however, is a very rare species globally (www.mindat.org; accessed January 2024) and has not been reported from Tsumeb. While no compositional analyses appear to have been published, the beaverite occurring at Tsumeb is understood to be beaverite-(Cu).

The presence of beaverite in near-surface ores from the first oxidation zone was verified by Gebhard (1999), based on a re-examination of samples first described by Maucher (1908a).

Beaverite was first recognised in the second oxidation zone from the East 49 Stope, a little above 30 Level by Geier et al. (1971) who noted its presence as a minor constituent of the type assemblage for tsumcorite, along with anglesite, arseniosiderite, beudantite, carminite, mimetite, pharmacosiderite and scorodite, hosted in a cherty dolomite breccia.

Keller (1984) described crusts and powdery coatings of canary-yellow beaverite in associations with adamite, leadhillite and malachite.

Beaverite occurs typically as bright yellow earthy crusts but is readily confused with yellow members of the tsumcorite group (notably gartrellite), and also possibly with betpakdalite-CaMg. Analysis is required for verification and unfortunately a high proportion of "beaverite" specimens in private and public collections have been mis-identified.

adamite; anglesite; arseniosiderite; beudantite; carminite; leadhillite; malachite; mimetite; pharmacosiderite; quartz; scorodite; tennantite-(Zn); tsumcorite