Arsentsumebite, (w. Anglesite and Covellite)

Chemistry: Pb2Cu(AsO4)(SO4)(OH)
Size: 70 mm
Owner: Mariusz Oleszczuk
Photographer: Mariusz Oleszczuk

A druse of well-crystallised, emerald-green arsentsumebite (XRD verified), extensively overgrowing diamond-shaped crystals of translucent white anglesite (to 6 mm).  

Interstitial to the arsentsumebite crystals, are sub-mm crystals of irridescent blue covellite (XRD verified).  These can just be made out in the close-up image (Photograph 2; FOV = 40 mm).    

The reverse of the specimen is also partly covered by micro-crystals of arsentsumebite, for which Tsumeb is the type locality.