Orpiment is a deep orange-yellow colored arsenic sulfide mineral with formula As2S3, It is found in volcanic fumaroles, low temperature hydrothermal veins, and hot springs and is formed both by sublimation and as a byproduct of the decay of another arsenic mineral, realgar.
Color : Orange-yellow to lemon-yellow to brownish-yellow
Lustre : Resinous or pearly, transparent or translucide
Hardness : 1.5 - 2 on the Mohs scale. Read More...