A sharpening stone, sometimes called an oil stone, is a tool used to sharpen a wide range of cutting tools.

Sharpening stones are usually made from silicone carbide, although there are more expensive types formed from diamond stone.

Sharpening stones, just like sandpaper, are available in different grades. Often one side of a sharpening stone is more abrasive than the other.

When using sharpening stones, water or oil should be applied to the stone's surface to lubricate it while the tool - for example a chisel - is being sharpened.