Luster is vitreous, adamantine, greasy or resinous. Crystals are translucent to transparent. Crystal System is isometric. Crystal Habits typically include well formed octahedral crystals but more commonly massive as well as granular and encrusting. Cleavage is imperfect.
Fracture is conchoidal.
Streak is white. Associated Minerals include quartz, stibnite , valentinite, kermesite, native antimony, stibiconite and other antimony minerals. Best Field Indicators are crystal habit, high luster, associations and specific gravity.