Luster is metallic. Crystals are opaque. Crystal Habits include the tabular, bladed or prismatic forms. Also massive, botryoidal, stalactitic and nodular. Sometimes as a replacement mineral of fossils and a pseudomorph of pyrite.
Cleavage is poor in two directions.
Fracture is uneven. Streak is greenish to brownish black. A sulfur smell is sometimes detectable. Associated Minerals are calcite , dolomite , quartz , goethite , fluorite , pyrrhotite , bornite , chalcocite , sphalerite , pyrite , galena and other sulfides. Best Field Indicators are crystal habit, smell and greenish tint.