Mimetite ps. Cerussite Tsumeb

Mimetite ps. Cerussite

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia

2.5 x 3.7 x 2 cm

ex. Marshall Sussman Collection

A striking and texturally rich pseudomorph in which mimetite has completely replaced Cerussite, preserving the crystal habit of the precursor mineral while adopting its own distinctive surface character. The specimen displays a warm golden-yellow to pale ochre coloration throughout, consistent with the arsenate composition typical of mimetite from this locality.

The pseudomorphic crystals exhibit blocky, tabular to stubby prismatic forms — a faithful echo of the cerussite architecture that once occupied this space. The surfaces are densely coated with a fine, granular to microcrystalline mimetite crust, imparting a velvety, almost frosted texture that catches light across every facet. Beneath this outer coating, glimpses of the fibrous and bladed internal structure hint at the complex replacement process that occurred during supergene alteration of the primary lead sulfide ore body.

The overall form is three-dimensional and sculptural, with multiple lobes rising from a shared base — a geometry inherited directly from a twinned or clustered cerussite precursor. Minor surface pitting and shallow vugs add further evidence of the dissolution-reprecipitation mechanism at work.

Tsumeb is one of the very few localities worldwide capable of producing pseudomorphs of this quality and size, a product of its exceptionally complex and chemically diverse oxidation zone. A superb example of supergene mineralogy and textbook-quality mineral replacement.​​​​​​​​​​​​​​​​