Luster is resinous, adamantine to sub-metallic. Crystals are translucent to transparent. They are terminated by a wedge-like dome. Also found as grains, crusts and earthy masses. Cleavage is good in one direction.
Fracture is subconchoidal.
Associated Minerals almost always include orpiment , also calcite , stibnite and other metal sulfide ores. Best Field Indicators are of course color as well as crystal habit, association with orpiment, softness and luster. 1995,1996,1999 by Amethyst Galleries, Inc.