suure Al2O3 sisaldusega (30-48 %) savi; lähtematerjal tulekindlate materjalide tootmiseks, samuti vormisavina suurendatud tulekindlusega liivvormide valmistamisel (vt tulekindlus), a mineral aggregate that has as its essential constituent the hydrous silicates of aluminum (Al2O3.mSiO2.nH2O) with or without free silica; it is used in commercial refractory products (see: refractoriness)