For your sharpening needs, (Norton) has a variety of Diamond Stones made of monocrystalline rather than polycrystalline diamonds. Mono diamonds resist fragmentation so they remain securely in place for extended life. These diamonds also maintain precision flatness longer. Norton standard bench stones, INDIAÂ® and CRYSTOLONÂ®, may be used wet or dry. All other stones should be used with water or preferably, with Norton sharpening stone oil. Proper stone lubrication floats away metal and abrasive dust particles that would clog up the stone and ultimately render it useless. INDIA stones are orange in color; CRYSTOLON stones are gray. Combination stones have different grit sizes on each side. Generally, the largest stone affordable is best for straight-edge sharpening as it allows use of the full surface for wider tools. For tools with curves or angles, there are specific products with special shapes for sharpening.