Realgar
Chemical Formula	As4S4 or AsS
Species	Sulfides
Crystal System	Monoclinic
Mohs Scale	1-2
Specific Gravity	3.56
Color	Red to yellow-orange; in polished section, pale gray, with abundant yellow to red internal reflections
Streak	Red-orange to red
Luster	Resinous, Greasy
Refractive Index	n = 2.538 n = 2.684 n = 2.704
Diaphaneity	Transparent
Cleavage	Distinct/GoodGood on , less good on
Crystal Habit：Prismatic striated crystals; more commonly massive, coarse to fine granular, or as incrustations