Gerdtremmelite from the one and only known occurrence at Tsumeb mine, Namibia. One of the super rarities from Tsumeb, this zinc iron aluminium arsenate hydroxide definitely requires a microscope for viewing, but is a cracking micromount specimen. A cluster of three dark brown to cinnamon brown Gertremmelite rosettes 0.9, 0.7 and 0.5 mm in diameter sit upon a thin sliver of matrix with more rosettes of Gerdtremmelite along one side. The rosettes display the typical form for this rare species. Thin, pale yellow to cream, sectile platy microcrystals of Powellite are also present, identical in appearance to an image of the Co-Type material from which Gerdtremmelite was described. Glassy microcrystals of Scorodite are present on the back of the specimen. An extremely rich, crystallized specimen of this absolute rarity. The only negative that I can think of is that some of the grease within the mineral tack has permeated into the matrix of the specimen.
