This remarkable Jekyll and Hyde piece from Tsumeb is like no other we have seen from this famous locality! The two sides are so conspicuously different with the Hyde side completely dominated by glossy, black-green botryoids of Heterogenite and the Jekyll side by translucent, white rhombs of Calcite dusted with Duftite. Heterogenite is an uncommon cobalt hydroxide and forms as a secondary alteration of primary cobalt-bearing ores. It is usually a "coating" or the ugly side mineral covering up something more beautiful, but in THIS case it is a really attractive piece! It's apparent that the Heterogenite formed early and Calcite was subsequently deposited on the Calcite followed by discontinuous patches of light olive green Duftite. Very trivial but some small bruising to both the Heterogenite and Calcite is noted, but only discernible up close and it shows off so nicely that, as a specimen for this species in a Tsumeb suite, I can quite easily accept any small bruises. A very unusual Tsumeb piece for its mineralogy and paragenesis. old John E. MacDonald Fine Minerals label.