Duftite

Duftite


Composition: PbCu(AsO4)(OH)
Crystal System : Orthorhombic
Lustre : Sub-vitreous, resinous, waxy, dull
Hardness (H) : 4.5
Specific Gravity (S.G) : 6.12
IMA Number: 1920
IMA Status: Grandfathered
Discovered By: Friederich Karl Biehl (German mineralogist)
Named for: Gustav Duft (a Director of OMEG)
References: Pufahl (1920)

Tsumeb is the Type Locality

Distribution

Common.  Occurs in all three oxidation zones.

Occurrence

  • Supergene
  • 1st Oxidation Zone
  • 2nd Oxidation Zone
  • 3rd Oxidation Zone

Paragenetic and General Notes

Duftite (Tsumeb type locality) occurs as olive to grey-green and dark-green crusts, sometimes sub-botryoidal.  Also as distinct green crystals exceptionally to 3 mm (Pinch and Wilson, 1977). Duftite is readily confused with conichalcite or mottramite. 

Modern studies (Kharisun et al., 1998; Jambor et al., 1980) have shown that the "β-duftite" of Guillemin (1956) is not a distinct polymorph but a Ca-rich duftite, intermediate in a continuous solid solution series between duftite and conichalcite. Duftite from the upper portion of the first oxidation zone is usually lead-dominant (the former duftite-α), while second oxidation zone duftite is usually calcium-bearing (the former duftite-β; Von Bezing et al., 2014.)

Duftite is reported to form pseudomorphs after the following minerals: azurite (rare); dolomite (rare); enargite (rare); mimetite(rare); tennantite (rare).