Abstract: This invention relates to the production of opal glasses having a creamy-white tint which are suitable for forming culinary articles. The opacity is obtained through precipitation of fluorides, preferably NaF. The creamy-white tint results from the association of Fe.sub.2 O.sub.3 with TiO.sub.2 and/or As.sub.2 O.sub.3 and/or CeO.sub.2, with the addition of nitrates. The preferred composition of the final glass consists essentially, in weight percent, of:______________________________________ SiO.sub.2 70-73 Fe.sub.2 O.sub.3 0.1-0.25 Na.sub.2 O 10.5-13 TiO.sub.2 0.1-0.7 Fluorine 4-5.5 As.sub.2 O.sub.3 0.05-0.4 Al.sub.2 O.sub.3 6-9 CeO.sub.2 0-0.2 CaO 0.2-1.7 B.sub.2 O.sub.3 0.5-3 BaO 1-3 ______________________________________The starting composition contains NaNO.sub.3 in a proportion of 0.2-2 by weight, counted as Na.sub.2 O with regard to the glass, or an equivalent quantity of another alkali metal or alkaline earth metal nitrate.

Abstract: This invention relates to the production of sodium fluoride opal glasses tinted in a shade lying in the range from "cream-like" to "beige" by an iron-sulfur system, the analyzed quantities of sulfur (S), sulfide ions (S.sup.-2), iron (Fe), and ferric ions (Fe.sup.+3) conforming to the following expressions:S.sup.-2 /S.gtoreq.0.1570.ltoreq.Fe.ltoreq.300 ppm0.05.ltoreq.Fe.sup.+3 /Fe.sup.+2 .ltoreq.1and 3.ltoreq.S.sup.-2 .ltoreq.160 ppm when the ZnO content is below 0.1%. The glasses are especially applicable for use in culinary ware.

Abstract: This invention is concerned with the preparation of thermally crystallizable enamels suitable for application to glass-ceramics, particularly glass-ceramics having coefficients of thermal expansion less than 15.times.10.sup.-7 /.degree.C. The enamels are capable of being fired to maturity simultaneously with the precursor glass body being crystallized to a glass-ceramic. The enamels consist essentially, expressed in weight percent on the oxide basis, of:SiO.sub.2 : 36-58Al.sub.2 O.sub.3 : 8.5-16CaO: 0.5-10PbO: 27-40K.sub.2 O: 0.