Heptasartorite
A very rare thallium-lead-arsenic sulfosalt — another recently approved member of the sartorite series.
Intro adapted from Wikipedia (CC BY-SA).
Heptasartorite is an IMA-recognized mineral species in the sulfosalt class, with the chemical formula Tl₇Pb₂₂As₅₅S₁₀₈.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Sartorite structural group.
Key properties: Mohs hardness 3–3.5; specific gravity 4.9; Dark brown streak; Metallic. Anisotropism: Moderate to weak in brown-violet and deep green tints. Bireflectance: Weak luster.
IMA symbol Hsat, IMA status: approved, named in 2015.
Found in dolostone.
It is found associated with Enneasartorite.
The name refers to a member of the sartorite homologous series with a seven-fold superstructure.