Al2O3.3H2O  As "Calcined" but stays in glaze suspension better. Can help with removing of finely dispersed bubbles in glazes. Can enhance Cr-Al pinks. Fine white granular powder increasing glaze viscosity, firing range and resistance to crystallisation. Very high melting temperature. 15%+ in a glaze can impart matt and opaque effects - best introduced from kaolin or frits. Al2O3.3H2O  Also, used in Batt Wash