Rutile Group / Corundum Group / FeTiO3 Pseudobrookite Group / Spinel Group / M2TO4 Ilmenite Group / Al2O3 Corundum Al2O3 Crystal System Trigonal Point Group / Crystal System Hexagonal Point Group / A2BO5 Perovskite Group / UO2 Uraninite UO2 Crystal System Cubic Point Group / Hematite Fe2O3 Trigonal Point Group / Al (MgAl) O4 (Inverse) Ilmenite Group / Tenorite HgO Montroydite Crystal System Hexagonal Point Group / Bixbyite Mn2O3 Crystal System Cubic Point Group / ZrO2 Rutile TiO2 Crystal System Tetragonal Point Group / Dense Pseudobrookite Group / Ferro / Bromellite BeO Crystal System Cubic Point Group / /