Aluminum Oxide - A blocky, hard grain best suited for sanding and grinding of ferrous and non-ferrous metals, wood and solid surface materials.
Silicon Carbide - A sharp, very hard and brittle grain best suited for sanding of glass, plastics, rubber, ceramics, solid surface materials and some non-ferrous metals.
Alumina Zirconia - A very hard and sharp grain that works well for grinding of stainless steel, spring steel, titanium and other hard steels and for dimensioning of wood.
Crocus -A natural abrasive of iron oxide particles. Used mostly for cleaning and polishing soft metals.
Emery - An abrasive that is a natural composite of Corundum and Iron Oxide. The grains are blocky, cut slowly, and tend to polish the material being abraded.
Garnet- A very sharp grain that cuts very quickly when new. Fractures quickly, keeping it sharp. Perfect for sanding wood end grains or for final-finish sanding of wood. Very economical.
Stearate - An additive that prevents loading when sanding soft resinous woods, after sealer coats and when working with soft ferrous or non-ferrous metals. Not an abrasive grain.