bog manganese[′bäg ′maŋ·gə‚nēs]
a highly dispersed mineral substance consisting of MnO2·n H2O and other hydroxides of manganese. It goes by various names, including earthy manganese and wad. Depending on the impurities it contains, bog manganese is divided into a number of varieties, including lampadite, containing CuO; tunnerite, containing ZnO; and asbolites, containing CoO + NiO.
Bog manganese forms powdery, contaminating masses, incrustations, dendritic films, and concretions. It is black or blackish-brown in color. Its density is 2, 800 to 4, 400 kg/m3; its hardness on the mineralogical scale is 1-4.
Bog manganese is widespread in nature as a product of the weathering of various manganese-containing minerals. It forms part of the composition of sedimentary manganese ores; it is formed in the benthic marine and lacustrine sediments. It is used as an ore along with other manganese minerals.