The Scotch-Brite Roloc high strength disc contains aluminum oxide abrasive mineral. Aluminum oxide is a popular choice among industrial professionals because of its cut-rate and long life. This mineral is a tough, durable abrasive that self-fractures to expose fresh cutting edges in use, whereas traditional abrasives, such as garnet, quickly wear down with use. - Due to its high cut-rate, hardness, strength and low heat retention, aluminum oxide mineral is widely used in grinding applications in addition to sanding and finishing use. Aluminum oxide is suitable on a wide variety of substrates in both woodworking and metalworking, including ferrous alloys.