An Abrasive is a material (usually a mineral), basically used to shape or finish a workpiece through rubbing which results in the workpiece being worn out by friction. Finishing a material often includes polishing in order to achieve a smooth and reflective surface, the process may also involve roughening as in satin,matte or beaded finishes.
Abrasives are shaped for various purposes. Natural abrasives are often sold as dressed stones, usually in the form of a rectangular block. Both natural and synthetic abrasives are commonly available in a wide range of shapes, often coming as bonded or coated abrasives, including blocks, belts, discs, wheels, sheets, rods and loose grains.