Often referred to as "ruby silver" due to its vibrant hue, proustite forms in prismatic or rhombohedral crystals, typically found in hydrothermal veins. Discovered in notable mining regions such as Germany, Chile, and Mexico, proustite has been a valuable source of silver throughout history.

Proustite occurs in hydrothermal deposits as a phase in the oxidized and supergene zone. It is associated with other silver minerals and sulfides such as native silver, native arsenic, xanthoconite , stephanite , acanthite , tetrahedrite and chlorargyrite .

Proustite Harker D (1936) The application of the three-dimensional patterson method and the crystal structures of proustite, Ag3 As S3, and pyrargyrite, Ag3 SbS3 _cod_database_code 1011161 Journal of Chemical Physics 4 381-390

Proustite is an interesting mineral that contains silver in its chemical structure. It is one of the few silver-bearing minerals that can exhibit transparency. Proustite is usually transparent, with deep-red crystals, but may also be a darker, more metallic-looking form.