Two growth habits of anatase crystals may be distinguished. It consists mainly of rutile or anatase. It is associated with magnetite, ilmenite, anatase, pyrite, marcasite, lepidocrocite and goethite. Generally, it is sourced from ilmenite, rutile, and anatase. Titanium dioxide occurs in nature as the minerals rutile and anatase. Naturally occurring pseudomorphs of rutile after anatase are also known. Visible-light-active nanosized anatase and rutile has been developed for photocatalytic applications. The titanium minerals are mostly anatase and rutile, and zirconium occurs in the mineral zircon. Additionally, butterfly wing mimetic structures have used to fabricate anatase titania photoanodes. Octahedrite is an obsolete synonym for anatase, one of the three known titanium dioxide minerals. Nanosized titanium dioxide, particularly in the anatase form, exhibits photocatalytic activity under ultraviolet (UV) irradiation. Anatase can be converted into inorganic nanotubes and nanowires. The most common delustrant is anatase titanium dioxide. Ultrafine anatase form is precipitated from sulfate solution and ultrafine rutile from chloride solution. Common titanium-containing minerals are anatase, brookite, ilmenite, perovskite, rutile, and titanite (sphene).