Chemistry: [Ca2(H2O)17Ca(H2O)6][Mo8As2Fe3+3O36(OH)]
Size: 28 mm
Owner: Malcolm Southwood
Photographer: Malcolm Southwood

Vitreous yellow crystals of betpakdalite-CaCa (to 0.75 mm), associated with colourless crystals of quartz (to 4 mm) on a siliceous matrix that includes a few blebs of unidentified steel-grey sulphide minerals. 

The betpakdalite has been verified by XRD, although the cation composition has not been determined.  However, all occurrences of betpakdalite at Tsumeb that are not associated with scorodite are believed to be betpakdalite-CaCa, which is by far the more common of the two species at this locality.