Heptasartorite

heptasartorite

enneasartorite

hendekasartorite

thallium

Images

Formula: Tl₇Pb₂₂As₅₅S₁₀₈
Valence: Tl¹⁺₇Pb²⁺₂₂As³⁺₅₅S^2-₁₀₈
Sulpharsenite of thallium and lead, sartorite group
Crystal system: Monoclinic
Specific gravity: 4.9 calculated
Hardness: 3 to 3½
Streak: Dark brown
Colour: Lead-grey, grey; rare deep red internal reflections
Environments

Sedimentary environments

Physical and optical properties of heptasartorite, enneasartorite and hendekasartorite are very similar, so that chemical analysis and/or single-crystal X-ray diffraction is needed to distinguish them.

Localities

At the type locality, the Lengenbach Quarry, Fäld, Binn, Goms, Valais, Switzerland, heptasartorite belongs to the late sulphide phases in the Pb–Tl–Ag–As deposit. It occurs in dolostone associated with enneasartorite (EJM 29.4.701-712, HOM).
Heptasartorite from the Lngenbach Quarry - Image

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