tehislik Al2O3-baasil valge keraamiline materjal, mida saadakse alumiiniumoksiidi sulatamisel elektriahjus; muuhulgas leiab kasutust nii tulekindla- kui abrasiivmaterjalina, alumina (Al2O3) produced using fusion of high purity calcined alumina in electric arc furnaces; used in many applications including abrasives, grinding wheels, refractories, ceramic shapes etc