rēˈalˌgär, -_gər noun
( -s )
Etymology: Middle English, from Medieval Latin, from Catalan, from Arabic rahj al-ghār powder of the mine
: an orange-red mineral As 4 S 4 or AsS that consists of arsenic sulfide and that occurs in monoclinic crystals or in granular or compact form, has a resinous luster, and burns with a bluish flame giving off arsenical and sulfurous fumes while burning (hardness 1.5-2, specific gravity 3.56) — see arsenic disulfide