Abstract: A noble glass composition which is based on a known potassium-zinc crystal glass composition suitable for chemical strengthening, in which most of contained ZnO component is replaced with a combination of less expensive oxides. The noble glass composition is easily melted in a tank and formed by machine into table wares, and provides a chemical strengthened crystal glass article which has high practical strength as tableware and can be subjected to washing with an alkali.

Abstract: [Object] To develop a noble glass composition which is based on a known potassium-zinc crystal glass composition suitable for chemical strengthening, in which most of contained ZnO component is replaced with a combination of far inexpensive other oxides, which is easily to melt in a tank and to form by machine into table wares, which satisfies the legal conditions as crystal glass specified in glass composition, refractive index, and density, and which is superior in chemical strengthening suitability; and to provide a chemical strengthened crystal glass article which has high practical strength as a table ware and can be subjected to washing with an alkali.