Arsentsumebite, (after Mimetite)

Size: 53 mm
Owner: Chris Amo
Photographer: John Schneider

Bright green pseudomorphs of arsentsumebite after mimetite occurred in considerable abundance, but only in the upper levels of the Tsumeb mine.  They were originally identified as bayldonite (after mimetite), but modern analysis shows that almost all such specimens are, in fact, arsentsumebite (after mimetite).

This specimen is accompanied by a hand-written German label dating the specimen to 1922.  Some of  the replaced crystals (which measure to 10 mm) have partly hollow cores and include some residual mimetite, as seen in the broken individuals at right of lower centre in the main photograph.