Brookite is a mineral composed of titanium dioxide (TiO2) and is one of the three main polymorphs of titanium dioxide, alongside anatase and rutile. It typically forms in a tetragonal crystal system and can appear in colors ranging from brown to black. Brookite is often found in metamorphic rocks and is known for its distinctive elongated crystals. This mineral is relatively rare compared to its counterparts and is primarily used in scientific research and industrial applications. Brookite can also be found in various locations around the world, including the United States, Brazil, and Italy, where it occurs in specific geological environments.