Anatase is a polymorph with 2 other minerals. Anatase as well as the minerals rutile and brookite have the same chemistry but different structures. Rutile is the more common of the 3, while anatase is the rarest and usually not available for sale under normal conditions. Anatase shares many of the properties as rutile such as luster, hardness and density. Anatase and rutile have the same symmetry despite having different structures. Anatase crystals are very distinctive and are not easily confused with any other mineral. Nice specimens of anatase are associated with quartz and are considered classics in the mineral world. In the US, it is found in Colorado.