What is Orpiment?
[[File:Orpiment mineral.jpg|thumb|Orpiment]] '''Orpiment''' is a [[mineral]]. Its chemical formula is [[arsenic trisulfide|As<sub>2</sub>S<sub>3</sub>]]. It is an orange to yellow mineral. It has a [[Mohs hardness]] of 1.5 to 2 and a [[specific gravity]] of 3.46. It melts at 300°C and [[oxidation|oxidizes]] to [[arsenic trioxide]] at higher temperatures. It is toxic because it gets a layer of arsenic trioxide on it by oxidation in the air. Orpiment was used as a [[pigment]] because it was one of the only yellow pigments that they could find. It is used to remove hair from [[hide]]s. [[Category:Minerals]]