Tsumeb is the Type Locality
Extremely rare. First oxidation zone.
- 1st Oxidation Zone
Paragenetic and General Notes
Despite its early discovery, tsumebite from the type locality remains exceptionally rare and elusive.
Tsumebite was described as a new mineral from a suite of specimens sold by Dr F. Kranz, of Bonn, to the University of Münster, in 1912. More or less simultaneously, but just a little too late, V.Rosicky, in Prague, described the same mineral on a specimen acquired from Wilhelm Maucher, and named it "Preslite" (Gebhard, 1999).
Tsumebite is typically well-crystallised, platy, always twinned, sometimes with multiple twinning and serrated re-entrants. Crystals are transparent, emerald-green or blue-green (not unlike dioptase).
The vast majority of specimens labelled as "tsumebite" in private collections are, in fact, arsentsumebite.
Tsumebite is reported to form pseudomorphs after the following minerals: mimetite (rare, doubtful status); pyromorphite (rare, doubtful status).