Proustite
Chemical Formula	Ag3AsS3
Species	Sulfates
Crystal System	Trigonal
Mohs Scale	2
Specific Gravity	5.625
Color	Scarlet-vermilion
Streak	Vermilion
Luster	Adamantine
Refractive Index	n = 3.087 - 3.088 n = 2.792
Diaphaneity	Translucent, darkens when exposed to light
Cleavage	Distinct/GoodDistinct on
Fracture	Irregular/Uneven, Conchoidal
Crystal Habit：Crystals prismatic and scalenohedral, massive, compact
Geological Setting：A late forming mineral in hydrothermal veins, also in the supergene zone.