Arsenic sesquisulphide, produced artificially as an amorphous lemon-yellow powder, and occurring naturally as a yellow crystalline mineral; -- formerly called auripigment. It is used in king's yellow, in white Indian fire, and in certain technical processes, as indigo printing.

a yellow mineral occuring in conjunction with realgar; an ore of arsenic

Arsenic trisulfide, As, a yellow mineral used as a pigment.