Orpiment
Chemical Formula
As2S3
Chemical Class
Sulfides
Properties
Orange yellow color mineral, lemon yellow and brownish yellow, with pearlescent or resin gloss, it has low hardness, 1.5 to 2, and 3.49 density.
Origin
Nevada, USA.
Curiosities
Due to low hardness and its unique and intense color, it was widely used as yellow gold pigment in several 18th century constructions.
Use
It is an arsenic (As) source mineral, and it is also very appreciated by collectors and museums.
Source: MM Gerdau - Museu das Minas e do Metal -