Proustite 6.84 ct

Proustite (Ag3AsS3) is a relatively rare silver mineral in nature, which occurs in its deposits mostly in millimetre sizes, only rarely do the crystals reach sizes above 5 mm. Proustite is very difficult to cut because this mineral is very soft. The offered piece comes from the Geschiber vein in Jáchymov, Bohemia. Today it is quite impossible to find crystals from which a stone this large could be cut. The raw material for this piece, including the original 130 year old label, was obtained in France from an old mineral collection. The offered piece is transparent (!) and has a deep red color; the cut size is 10,65 x 7,86 mm. Due to its photosensitivity (black on light!), the mineral is only suitable for a gemstone collection for very demanding collectors or as part of a museum collection. Proustite (Ag3AsS3) is very close to pyrargyrite (Ag3SbS3), both often occur together in the same deposits.