Abstract: Objects of marble-like glass ceramic are readily obtained from a thermally crystallizable composition consisting essentially of 50% - 65% SiO.sub.2, 3% - 13% Al.sub.2 O.sub.3, 15% - 25% CaO, and 2% - 10% ZnO when heat treated to convert at least a portion of the surface layer to crystals of .beta.-wollastonite.

Abstract: A crystallized glass article having a surface pattern like granite, marble or other natural stones, which is formed of a crystallizable glass material and is characterized by the existence of numerous needle-like .beta.-wollastonite crystals in various directions in a surface layer of the article. The crystallized glass article is produced by a heat-treatment of collected small crystallizable glass masses.

Abstract: A method for forming a glass article of a devitrifiable glass having an optimum working temperature in the vicinity of its liquidus temperature, wherein the temperature of the molten glass is, during the molding operation, maintained at considerably higher temperature than both the optimum working temperature and the liquidus temperature, the molded article is passed through water or a layer of wet granular materials floating in water before the temperature of the molded article drops down to the liquidus temperature and before the molded article is deformed to rapidly cool the article to a temperature below the devitrifying temperature.