Habit: Crystals uncommon, generally red to yellow-orange, short prismatic crystals, and as encrustations. Transparent when fresh, crystals tend to fade when exposed to light. Resinous to greasy Luster.
Environment: As a minor phase in Hydrothermal sulfide veins with orpiment and other arsenic minerals. It also forms as a sublimate around volcanoes, hot spring and geyser deposits
Etymology: From the Arabia rahu al ghar, powder of the mine. Realgar has been used for carvings, and as a red pigment.