Gabrielite

Gabrielite is a rare thallium sulfosalt mineral with a chemical formula of Tl₆Ag₃Cu₆(As,Sb)₉S₂₁ or Tl₂AgCu₂As₃S₇.

It was first reported in 2002 for its occurrence in the Lengenbach quarry, Binntal, Valais, Switzerland, and named after Walter Gabriel (born 1943), a Swiss mineral photographer. This region was transformed during the greenschist-garnet/amphibolite facies of metamorphism. Due to this many rare sulfosalts like gabrielite are found in this part of Switzerland.