Hausmannite is a manganese oxide mineral with the chemical formula Mn3O4. It typically appears as black or brownish-black crystals and has a metallic luster. Hausmannite is often found in metamorphic rocks and can form in hydrothermal environments, making it an important mineral for understanding geological processes. This mineral is named after the German mineralogist Gustav Hausmann, who contributed to the study of minerals in the 19th century. Hausmannite is used in various applications, including ceramics and batteries, due to its unique properties and the presence of manganese, an essential element in many industrial processes.