White fused alumina—almost as hard as a diamond

White fused alumina is a synthetic product that is created by melting high-grade aluminium oxide in an electric arcing process—accordingly the proportion of aluminium oxide is over 99%. Besides the transparency, an excellent property of white fused alumina is the extraordinarily high degree of hardness (9 on a 10-point scale) – only diamonds are harder. Thanks to its exceptional hardness, wear resistance, and high-temperature stability, white fused alumina is widely used as an abrasive, blasting medium, and cutting tool material.