peamiselt karborundist, ka magnetiidist (Fe3O4) ja muudest mineraalidest koosnev peeneteraline moondekivim, millest valmistatakse abrasiivmaterjale ja -tööriistu, an impure natural material consisting of a mixture of corundum (Al2O3), magnetite (Fe3O4) or haematite (Fe2O3) and in powdered form used in production of grinding and polishing materials (paper, cloth, buff, wheel)