Orpiment
Chemical Formula	As2S3
Species	Sulfides
Crystal System	Monoclinic
Mohs Scale	1-2
Specific Gravity	3.49
Color	Lemon-yellow to golden or brownish yellow
Streak	Pale lemon-yellow
Luster	Pearly
Refractive Index	n = 2.400 n = 2.810 n = 3.020
Diaphaneity	Transparent
Cleavage	PerfectPerfect imperfect
Crystal Habit：Commonly in foliated columnar or fibrous aggregates; may be reniform or botryoidal; also granular or powdery; rarely as prismatic crystals