Zincostottite

zincostottite

nancyrossite

karlseifertite

germanite

Images

Formula: ZnGe(OH)6
Hydroxide, stottite subgroup, non-stoichiometric perovskites group, perovskite supergroup, germanium-bearing mineral
Crystal system: Tetragonal
Specific gravity: 3.834 calculated
Hardness: 4½
Streak: White
Colour: Colourless
Luminescence: Not fluorescent under long or short wave UV
Solubility: Soluble in dilute hydrochloric acid at room temperature
Environments

Hydrothermal environments

Zincostottite is a new mineral, approved in 2024 and to date (May 2025) pending publication.

Localities

At the type locality, the Tsumeb Mine, Tsumeb, Oshikoto Region, Namibia, zincostottite was found as a secondary phase alongside siderite, malachite and quartz on fracture surfaces in a germanium-rich sulphide ore assemblage consisting of germanite, bornite, chalcocite and tennantite-(Zn). Zincostottite crystals on the type specimens are translucent and yellowish in colour and appear to have been strongly etched after formation.
Zincostottite is the Zn analog of stottite, also discovered at the Tsumeb Mine. The Tsumeb Mine is a unique locality for germanium mineralisation. With the addition of zincostottite, nancyrossite and karlseifertite in 2024, there are now (May 2025) 16 germanium minerals for which the Tsumeb Mine is the type locality out of 41 total minerals with essential Ge. Apart from the germanium perovskite supergroup minerals stottite, zincostottite and nancyrossite, the Tsumeb Mine is also the type locality for söhngeite, another member of the non-stoichiometric perovskites group (AM 110.5.827-828).
Zincostottite from the Tsumeb Mine - Image

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