Arsenoústalečite

arsenoustalecite

stibioustalecite

hakite-(Hg)

berzelianite

Images

Formula: Cu₆Cu₆(As₂Te₂)Se₁₃
Selenide, ústalečite subgroup, tetrahedrite group, arsenic- and tellurium- bearing mineral
Crystal System: Isometric
Specific gravity: 5.730 calculated
Hardness: 3½ to 4
Colour: Dark grey
Environments

Hydrothermal environments

Arsenoústalečite is a new mineral, approved in 2023 and to date (May 2024) reported only from the type locality.

Localities

At the type locality, the Ústaleč U occurrence, Ústaleč, Nalžovské Hory, Klatovy District, Plzeň Region, Czech Republic, arsenoústalečite occurs as rare anhedral grains, up to 40 μm in size, in a calcite gangue, associated with stibioústalečite, hakite-(Hg), berzelianite and uraninite. Arsenoústalečite is dark grey, with a metallic lustre (MM 88.2.127-135).

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