cerussite (w. malachite after azurite, on smithsonite)

azurite; malachite; smithsonite

A single crystal of etched, colourless, water-worn cerussite (14 mm) rests on a heavily etched blocky pseudomorph of malachite after azurite (Exhibit 2), one of three such pseudomorphs on the specimen. The matrix consists largely of intergrown colourless-white rhombs of smithsonite (to 2 mm) which have a chalky, cream-coloured surface patina (Exhibit 3). Spherules of malachite (to 1 mm) and sparse bladed crystals of pristine blue azurite (to 0.8 mm) are locally present on the smithsonite. The colour of the matrix is due largely to iron staining, but it is noted that traces of pocket clay remain on parts of the specimen.

This was specimen 542 in the collection of Wilhelm Klein, production manager at Tsumeb between 1916 and 1939. His catalogue records that it is from the Open Pit at the top of the first oxidation zone.