Fahleite


Composition: CaZn5Fe3+2(AsO4)6.14H20
Crystal System : Orthorhombic
Colours: Yellow-grey, green
Lustre : Silky, pearly
Hardness (H) : 2
Year of Discovery: 1982
IMA Number: 1982-061
IMA Status: Approved
Discovered By: Rolfe Fahle (German dealer)
Named for: Discoverer

Tsumeb is the Type Locality

Distribution

Extremely rare. The type specimen is described as originating from the "deep oxidation zone" (Medenbach et al., 1988) and from the "deepest levels" (Von Bezing et al., 2014).

Occurrence

  • Supergene

Paragenetic and General Notes

On the type specimen, fahleite occurs as yellow-green fibrous crystals to 10 mm, associated with gypsum, lavendulan, cuprian adamite, conichalcite, tsumcorite and calcite (Von Bezing et al., 2014). Since the description of the type material, another habit of "fahleite" has been discovered, as green, glass-like fragments (resembling the unknowns GS1 and GS2 of Gebhard, 1999). Microprobe analysis confirms that these share the same composition as fahleite, but we have yet to see confirmation that the material is structurally equivalent.