Akimotoite
Akimotoite is a rare silicate mineral ((Mg,Fe)SiO3) in the ilmenite group of minerals. It is polymorphous with bridgmanite, a natural silicate perovskite, which, on the contrary, is regarded as the most common mineral on Earth. Akimotoite has a vitreous luster, is colorless, and has a white or colorless streak. It crystallizes in the trigonal crystal system in space group R3. It is the silicon analogue of geikielite (MgTiO3).