Title
pharmacosiderite
Composition
KFe3+4(AsO4)3(OH)4·6-7H2O
Crystal System
Cubic
Status at Tsumeb
Believed valid
Abundance
Extremely rare
Distribution
Second oxidation zone.
Paragenesis
Supergene.
Type Locality
No
Entry Type
Species TSNB273
General Notes
The earliest published record of pharmacosiderite at Tsumeb is that of Geier et al. (1971) who recognised the mineral as a very minor component of the type assemblage for tsumcorite. In a "cavernous" part of the ore body at E49 on 30 Level a complex paragenesis was observed including anglesite, beudantite, carminite, arseniosiderite, beaverite, scorodite, pharmacosiderite and tsumcorite.
Bartelke (1976; citing unpublished TCL reports and a 1976 pers. comm. from Walter Kahn) noted that small, translucent, admantine, yellow to olive-green crystals of pharmacosiderite were found on 30 Level, information repeated by Pinch and Wilson (1977), Keller (1984) and Gebhard (1999).
Keller and Innes (1986) recorded an occurrence of pharmacosiderite from the West 40 Stope on 32 Level where they also found paradamite, betpakdalite, pharmacosiderite and ojuelaite.
Associated Minerals
anglesite; arseniosiderite; beaverite-(Cu); betpakdalite-CaCa (?); beudantite; carminite; metazeunerite; ojuelaite; paradamite; pharmacosiderite; scorodite; tsumcorite