Manganese Dendrites: Mineral information, data and localities.
Black dendritic films of various visually indistinguishable black manganese oxides, may consist of birnessite, coronadite, cryptomelane, hollandite, romanèchite, todorokite or other species. Many manganese minerals have similar strong Xray poweder diffraction lines and linebroadening can make Xray diffraction identification ineffectual.