Abstract: The present invention is directed to glasses exhibiting annealing points between 682.degree.-702.degree. C., linear coefficients of thermal expansion (25.degree.-300.degree. C.) between 57-59.times.10.sup.-7 /.degree. C., and excellent resistance to attack by HCl and Na.sub.2 CO.sub.3 consisting essentially, in weight percent, of______________________________________ SiO.sub.2 56-60 Na.sub.2 O 0-3 Al.sub.2 O.sub.3 12-15 K.sub.2 O 0-3 B.sub.2 O.sub.3 5.5-7 Na.sub.2 O + K.sub.2 O 0.5-3. CaO 19-24.

Abstract: An ivory-colored, opaque glass-ceramic having a beta-spodumene solid solution as its primary crystal phase, and a method of controlling color in the glass-ceramic. The glass-ceramic is produced from a Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 precursor glass containing 3-6% TiO.sub.2 +ZrO.sub.2 as a nucleating agent and having colorants controlled at levels of up to 20 ppm Co.sub.3 O.sub.4, up to 1000 ppm Fe.sub.2 O.sub.3 and 1000-2000 ppm CeO.sub.2.

Abstract: An opaque glass-ceramic having a beta-spodumene solid solution as its primary crystal phase, and a method of controlling color in the glass-ceramic. The glass-ceramic is produced from a Li.sub.2 O-Al.sub.2 O.sub.3 -SiO.sub.2 precursor glass containing 3-6% TiO.sub.2 +ZrO.sub.2 as a nucleating agent and having colorants controlled at levels of 1500-4,000 ppm Fe.sub.2 O.sub.3, 1500-4000 ppm CeO.sub.2 and 50-500 ppm V.sub.2 O.sub.5.

Abstract: A colored glass-ceramic and method of making it. The glass-ceramic has a primary crystal phase selected from the group consisting of beta-quartz solid solution and beta-spodumene solid solution, containing an amount of TiO.sub.2 effective as a nucleating agent up to 6% by weight, 700-900 ppm Fe.sub.2 O.sub.3 and 550-3000 ppm Co.sub.3 O.sub.4, the glass-ceramic having a beta-quartz solid solution as a primary crystal phase being transparent and having a color defined by the color coordinates x=0.2200-0.3100, y=0.0200-0.2400 falling within color box ABCDA in FIG. 1 in the drawings, and the glass-ceramic having a beta-spodumene solid solution as a primary crystal phase being opaque and having a color defined by the color coordinates x=0.2480-0.2880, y=0.2000-0.3150 falling within color box JKLMJ in FIG. 2 in the drawings. Reddish-purple and violet colors are obtained in transparent, beta-quartz glass-ceramics, while light to dark blue colors are obtained in opaque, beta-spodumene glass-ceramics.

Abstract: A colored, transparent glass-ceramic having a beta-quartz solid solution as its primary crystal phase, and a method of producing the glass-ceramic. The glass-ceramic is produced from a Li.sub.2 O--Al.sub.2 O.sub.3 --SiO.sub.2 precursor glass containing an amount of TiO.sub.2 effective as a nucleating agent up to about 6%, and having a color package composed of 10-20 ppm Co.sub.3 O.sub.4, 550-650 ppm Fe.sub.2 O.sub.3, 19.5-20.5% Al.sub.2 O.sub.3 and 2.5-3.0% Li.sub.2 O.

Abstract: A method of varying the color in a glass-ceramic material having a beta-quartz solid solution as the predominant crystal phase which comprises controlling the Al.sub.2 O.sub.3 level between 19 and 20% by weight, the Fe.sub.2 O.sub.3 level between 700 and 900 ppm and the Co.sub.3 O.sub.4 level between not over 15 ppm and 140 ppm. An amber color is obtained with 20-40 ppm Co.sub.3 O.sub.4 and a burgundy color with 120-140 ppm Co.sub.3 O.sub.4. Co.sub.3 O.sub.4 in a compatible carrier may be added to molten glass as a forehearth additive.

Abstract: A transparent glass-ceramic and an article of cookware formed therefrom. The glass-ceramic has as its primary crystal phase a beta-quartz solid solution, contains an amount of TiO.sub.2 effective as a nucleating agent up to about 6%, and has a color package composed of 50 to 150 ppm Co.sub.3 O.sub.4, 50 to 250 ppm NiO and 400 to 1000 ppm Fe.sub.2 O.sub.3 that provides a burgundy color.

Abstract: This invention relates to the production of opaque, beige-tinted glass-ceramic articles consisting essentially, in weight percent, of______________________________________ SiO.sub.2 66-70 TiO.sub.2 3.5-5.5 Al.sub.2 O.sub.3 16.5-19.5 CeO.sub.2 1.5-2.75 Li.sub.2 O 2-4 As.sub.2 O.sub.3 0-1.5 MgO 1-5 F 0-1.2 ZnO 0.5-2 ZrO.sub.2 0-2.5 Na.sub.