Often the crystals are platy with a hexagonal outline and the hemimorphic character is then not easily distinguished. Color is light to dark brown almost black. Luster is resinous to dull. Transparency crystals are transparent to translucent. Also seen as acicular radiating crystal groups or as botryoidal crusts layered with galena and sphalerite .
Fracture is uneven.
Streak is light brown. Striations on pyramidal faces parallel to base, an index of refraction of 2.36 - 2.38 and some specimens fluoresce orange under UV light. Associated Minerals include galena , sphalerite and pyrite . Best Field Indicators are crystal habit, streak, cleavage, softness and associations.