An excellent all-purpose stone for polishing includes brown aluminum oxide, a faceted abrasive grit that is tough and blocky. For roughing applications, it can be used dry, but it is typically used wet. It is advised to use it on soft non-ferrous metals like aluminum and beryllium as well as mold and tool steels of all hardnesses, including A2, D2, S7, H13, P20, and 420SS.