The extreme hardness of corundum makes it especially useful as an abrasive. Crushed corundum is processed to remove impurities and then screened to produce uniformly sized granules and powders. These are used for grinding media, polishing compounds, sand papers, grinding wheels, and other cutting applications.

Some problems with using natural corundum as an abrasive are that the deposits are usually small, irregular in shape, and the corundum is of variable quality. They are not reliable sources of consistent-quality material needed to run a manufacturing process. Synthetic corundum, produced using calcined bauxite, has become a more reliable source with more consistent properties. It has replaced natural corundum in most manufactured products.