PURPOSE: To obtain an opal glass composition capable of forming the opal glass coat of enamelware requiring hot water resistance such as an enameled bathtub by providing a composition consisting of a specified mol% each of SiO2, B2O3, TiO2 or ZrO2, Li2O and fluoride except water.

CONSTITUTION: This opal glass composition has a composition ≥98mol% of which except water consists of, by mol, 49W64, especially 49W59% SiO2, 3W 12, especially 5W12% B2O3, 3W15, especially 8W15% RO2, 24W30 R2'O and 3W 7% fluoride as F2. RO2 is TiO2 or ZrO2, and R2'O is only Li2O or Li2O and Na2O or K2O in (Li2O)/(Na2O or K2O)>1.