Anatase - TiO₂

Habit: Brown, indigo-blue, green, gray, black. Crystals pseudo-octahedral, less commonly prismatic. Transparent when light colored, to nearly opaque when deeply colored, Adamantine to Metallic Luster

Environment: Usually secondary, derived from other titanium-bearing minerals. Is typically found in veins or crevices of the alpine type in gneiss and schists, associated with brookite, quartz, hematite, chlorite and titanite.

Etymology: Named for the Greek anatasis, extension, alluding to the greater length of the common pyramidal faces compared to other tetragonal minerals.

Anatase, brookite and rutile are all polymorphs, meaning they all have the same chemical composition (TiO2), but differ in crystal structure.