An excellent micaceous specimen from the type locality, consisting of elongate, platy, subhedral crystals of gray-black plumboferrite up to 1.5 mm inter-grown with brown-black, fine-grained, granular hausmannite and localized, cream-colored, discontinuous bands of dolomite. Plumboferrite is a lead iron manganese oxide. The Jakobsberg mine is situated in the Jajobsberg iron-manganese ore field in Sweden and is the type locality for several mineral species. Swedish Museum of Natural History label. Ex. Paulo Matioli collection.