Sandpaper Grit Chart & Guide - Grainger KnowHow
More Facts on Sandpaper Types. Besides the grits and grades, sandpaper is made out of materials that vary chemically. It can be made from the grains of a natural mineral called garnet, or from synthetic ones like aluminum oxide, alumina-zirconia or silicon carbide.Irrespective of the sandpaper you work with, it must have a strong bond between the sandpaper grit and its backing material.