Title
anhydrite
Composition
CaSO4
Crystal System
Orthorhombic
Status at Tsumeb
Confirmed
Abundance
Very rare
Distribution
Second oxidation zone; country rocks (dolostone stratigraphy)
Paragenesis
Supergene; rock-forming (diagenetic).
Type Locality
No
Entry Type
Species TSNB13
General Notes
Anhydrite occurs in evaporite associations (with gypsum and sulphur) in the T7 dolomite stratigraphy, between surface and 23 Level (Hughes 1987).
In January and February of 1980, anhydrite was found as part of an unusual paragenesis on oxidised lead ore, in the North-East Stope on 35 Level (Keller 1981; Keller and Bartelke 1982). Here, anhydrite was associated with chalcanthite, leightonite, lammerite, unidentified silicates, and a tsumcorite group mineral that was later determined to be an iron-bearing thometzekite. Keller and Bartelke (1982) proposed the following paragenesis:
R/7: primary sulphides >> chalcocite >> lammerite >> unidentified silicates >> TK-like mineral [thometzekite] >> anhydrite >> leightonite >> chalcanthite >> gypsum
Associated Minerals
chalcanthite; chalcocite; dolomite; gypsum; lammerite; leightonite; sulphur; thometzekite
