Pseudobrookite is a rare mineral that belongs to the group of oxide minerals. It has a chemical composition similar to the mineral brookite and is often found as an accessory mineral in igneous rocks. Synonyms for pseudobrookite include black titanium oxide, diallmaierite, and yimengite. These minerals have similar physical properties to pseudobrookite and are difficult to distinguish from each other. Black titanium oxide and diallmaierite are both black minerals with a characteristic metallic luster, while yimengite is a brownish-black mineral with a greasy luster. Despite their similarities, each of these minerals has unique features that make them interesting to study for mineralogists and geologists.