The terminations are generally blunted with domes and minor pyramid faces. The crystals are striated lengthwise. Crystals are usually grouped into tight bundles and columnar, massive and fiberous forms are also known. Penetration and contact twinning does occassionally occur. Cleavage is perfect in one direction lengthwise and good to fair in two other directions, one lengthwise at near right angles to the first one and one basal.
Fracture is uneven.
Streak is reddish to brownish black. Associated Minerals are calcite , barite , garnets , limonite , siderite , pyrolusite and other manganese minerals. Alters to pyrolusite which can coat the crystals, dulling the luster and can affect a streak test. Best Field Indicators are crystal habit, luster, striations, color and streak.