... , 9.0 Mohs scaleMagnetic Material 0.0076%Grain Sizes Available (F):12, 14, 16, 20, 22, 24, 30, 36, 40, 46 ... , 54, 60, 70, 80, 90, 100, 120, 150, 180, 220.Grain Size Distribution :Upon ANSI B74.12-2001 ... -1:2006 or ISO 8486-1 Brown Fused Aluminum Oxide F Grit for vitrified bonded grinding wheels.