Modification of ASTM C 621 is needed in order to determine the corrosion of the material MoSi₂ by molten glass since this material reacts with the prescribed platinum crucible. The latter was replaced with a fusion-cast alumina-zirconia-silica refractory crucible. A correction for the width of the saw kerf is suggested. The modified method was carried out on a number of cylindrical samples in molten E-glass at 1550°C. The specimen-glass interfacial regions were characterized using SEM, EDS, and XRD.