Tags: Chemical Substance, Mineral.
Realgar α-As4S4 is an arsenic sulfide mineral also known as ruby sulphur or ruby of arsenic. It is a soft sectile mineral occurring in monoclinic crystals or in granular compact or powdery form often in association with the related mineral orpiment (As2S3). It is orange-red in colour melts at 320 °C and burns with a bluish flame releasing fumes of arsenic and sulfur. Realgar is soft with a Mohs hardness of 1.5 to 2 and has a specific gravity of 3.5. Its streak is orange colored.
