Hausmannite is a complex oxide, or a mixed oxide, of manganese containing both di- and tri-valent manganese. Its chemical formula can be represented as , or more simply noted as , or , as commonly done for magnetite (), the corresponding iron oxide. It belongs to the spinel group and forms tetragonal crystals. Hausmannite is a brown to black metallic mineral with Mohs hardness of 5.5 and a specific gravity of 4.8.
The type locality is Oehrenstock (Öhrenstock), Ilmenau, Thuringian Forest, Thuringia, Germany, where it was first described in 1813.