Manganese is a strategically valuable metal since it is an essential ingredient in steel and other alloys. Color is black to gray. Luster is metallic to dull. Crystals are opaque, translucent in only thin splinters. Crystal Habit is typically massive and granular.
Crystals are uncommon and tabular.
Cleavage is good , but rarely seen except in rare large crystals. Fracture is conchoidal to uneven. Hardness is approximately 3, but is variable. Streak is black. Associated Minerals are limonite , hematite , quartz , manganite , psilomelane , pyrolusite and other manganese and iron oxide minerals.