Arsenohopeite

TSNB28
Mineral
Second oxidation zone (?)Supergene

Mineral Species

Arsenohopeite

Type Locality

Yes

Composition

Zn3(AsO4)2∙4H2O

Crystal System

Orthorhombic

Status at Tsumeb

Confirmed (type locality)

Abundance

Extremely rare

Distribution

Second (?) oxidation zone

Paragenesis

Supergene

Entry Number

Species; TSNB28

Type Mineralogy

Arsenohopeite, IMA 2010-069, was identified from a single polycrystalline grain (Neuhold et al. 2012) and is probably from the second oxidation zone. Arsenohopeite is the orthorhombic polytype of davidlloydite and the arsenate analogue of hopeite and was named in allusion to the latter relationship. The type specimen is conserved at the Naturhistorisches Museum, Vienna, Austria (catalogue number N8167).

General Notes

The arsenohopeite grain of the type specimen is colourless-blue and associated only with fibres of an unidentified white zinc arsenate. However, the authors noted that the type specimen was received in a vial which also contained fragments of adamite, leiteite, köttigite, quartz, schneiderhöhnite, carbonates and ore minerals; accordingly, there is a speculative possibility that these species occurred together in situ. They also observed that these minerals are typical of the second oxidation zone which may therefore also be the source of the arsenohopeite.

Bowell and Mocke (2018) reported arsenohopeite on material believed to be from the West 30 ore body in the second oxidation zone, although the level number was not recorded. They stated that the specimen also included adamite, austinite, calcite, goethite, smithsonite, stranskiite and willemite. The means of identification was not disclosed.

The list of associated minerals is tentative, based on the fragments accompanying the type specimen; it is noted that the list is somewhat reminiscent of the East 9 Pillar assemblage on 31 Level (see Keller and Bartelke 1982).

Associated Minerals

adamite; austinite; calcite; goethite; köttigite; leiteite; quartz; schneiderhöhnite; smithsonite; stranskiite; willemite