Color is dark brown or black. Luster is submetallic to metallic. Minor pyramidal faces may truncate only the top and bottom points, giving evidence of its tetragonal symmetry instead of the isometric octahedron. Twinning is common and repeated. Also granular and massive.
Cleavage is perfect in one direction, basal.
Fracture is uneven. Streak is brown. Associated Minerals include psilomelane , pyrolusite , Bixbyite and other manganese minerals. Best Field Indicators are crystal habit, color, hardness, cleavage, density and locality.