Composition: CaZn2H(AsO4)2OH
Crystal System : Monoclinic
Colours: Colourless, white
Lustre : Vitreous, silky
Hardness (H) : 4.5
Specific Gravity (S.G) : 4.31
Year of Discovery: 1976
IMA Number: 1978-028
IMA Status: Approved
Discovered By: Prosper J. Williams (Canadian dealer)
Named for: Discoverer
References: Gait et al. (1979)

Tsumeb is the Type Locality


Extremely rare. The level from which the type specimen was recovered is unknown.


  • Supergene
  • 2nd Oxidation Zone

Paragenetic and General Notes

Prosperite occurs as radiating groups of slender, white to colourless crystals to 10 mm in length, and 1 mm in diameter.

On the type specimen prosperite occurs in vugs in oxidising chalcocite ore. Two types of vugs were observed.

In the first, the prosperite is associated with druses of bright green conichalcite and pale blue-green rosettes of adamite crystals.

In the second type, the vugs are lined with dull, pale-green druses of cuprian austinite, and also contain adamite and prosperite.

The chalcocite in the matrix contains minute blebs of silver-amalgam, and cuprite was also identified on the matrix. Several then-unknown new minerals were also noted (Gait et al., 1979). Subsequently, Keller and Bartelke (1982), listed these additional species as koritnigite, gaitite, and o'danielite - all new minerals described from Tsumeb between 1978 and 1979.