Sharpening stones are also known as whetstones and are used to grind and hone various tools and blades. Sharpening stones can be natural or artificial, with artificial stones being bonded abrasives such as silicon carbide, aluminum oxide, or diamond. A diamond plate stone is coated with diamond grit bonded to a rigid block. Grit, measured in microns, describes the aggressiveness of the stone. A higher grit number indicates greater density of smaller particles, producing a finer finish. Generally, synthetic bonded abrasives provide a faster cutting action than natural stones.