Tennantite with Smithsonite from Namibia, Oshikoto Region, Tsumeb

Tennantite with Smithsinite (var. Cobaltoan) Coating

Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia

7 x 5.7 x 3 cm

A cluster of large, sharp tetrahedral tennantite crystals , the classic pseudo-cubic/tetrahedral habit typical of Tsumeb coated by a drusy crust of pale pink smithsonite that closely follows the underlying crystal faces and edges without obscuring their geometry. The coating is sugary in texture, giving the tetrahedral faces a frosted, granular sheen. A small area of exposed dark, metallic tennantite is visible in one cavity, confirming the sulfosalt core beneath the smithsonite crust.

Contrasting sprays of pale pink, botryoidal cobaltoan smithsonite crystallize along the margins and in recesses of the specimen, their rounded, mammillary habit distinct from the sharp-edged, smithsonite-coated tennantite crystals they accompany. The assemblage reflects the secondary carbonate mineralization that developed over primary sulfosalts during supergene oxidation at Tsumeb, without the original tennantite crystal material having been consumed or replaced.