Color is steel gray to silver. Luster is metallic. Transparency crystals are opaque. Crystal Habits include bladed or acicular crystals often bent or curved due to twinning, also granular and massive. Cleavage is perfect in the lengthwise direction.
Fracture is irregular.
Streak is a dark gray. Associated Minerals include quartz , calcite , gold , arsenopyrite and other sulfides. Best Field Indicators are crystal habit, softness and flexibility.