Crystallizable glasses, glass-ceramics, IXable glass-ceramics, and IX glass-ceramics are disclosed. The glass-ceramics exhibit -spodumene ss as the predominant crystalline phase. These glasses and glass-ceramics, in mole %, include: 60-75 SiO.sub.2; 10-18 Al.sub.2O.sub.3; 5-14 Li.sub.2O; and 4.5 B.sub.2O.sub.3. The glass-ceramics also have a Vickers initiation crack threshold of at least about 25 kgf.

A black lithium silicate glass ceramic is provided. The glass ceramic includes lithium silicate as a primary crystal phase and at least one of petalite, -quartz, -spodumene, cristobalite, and lithium phosphate as a secondary crystal phase. The glass ceramic is characterized by the color coordinates: L*: 20.0 to 40.0, a*: 1.0 to 1.0, and b*: 5.0 to 2.0. The glass ceramic may be ion exchanged. Methods for producing the glass ceramic are also provided.

A group of glass-ceramic compositions nucleated with ZrO.sub.2 and P.sub.2O.sub.5 can develop a microstructure composed of spherulite grains, which produce a high fracture toughness (about 1.5 MPa.Math.m.sup.0.5 or higher). Also, the glass-ceramic articles can be cerammed to have a CTE value of 3010.sup.7/ C. or lower.

Transparent, dyed cook top or hob with improved color display capability, consisting of a glass ceramic with high quartz mixed crystals as predominant crystal phase, whereby the glass-ceramic contains none of the chemical refining agents arsenic oxide and/or antimony, with transmission values of greater than 0.1% in the range of the visible light within the entire wavelength range greater than 450 nm, a light transmission in the visible of 0.8-2.5% and a transmission in the infrared at 1600 nm of 45-85%.

Glass-ceramics exhibiting a Vickers indentation crack initiation threshold of at least 15 kgf are disclosed. These glass-ceramics may be ion exchangeable or ion exchanged. The glass-ceramics include a crystalline and amorphous phases generated by subjecting a thin precursor glass article to ceramming cycle having an average cooling rate in the range from about 10 C./minute to about 25 C./minute. In one or more embodiments, the crystalline phase may comprise at least 20 wt % of the glass-ceramics. The glass-ceramics may include -spodumene ss as the predominant crystalline phase and may exhibit an opacityabout 85% over the wavelength range of 400-700 nm for an about 0.8 mm thickness and colors an observer angle of 10 and a CIE illuminant F02 determined with specular reflectance included of a* between 3 and +3, b* between 6 and +6, and L* between 88 and 97.

A composition includes: 30 mol % to 60 mol % SiO.sub.2; 15 mol % to 35 mol % Al.sub.2O.sub.3; 5 mol % to 25 mol % Y.sub.2O.sub.3; 0 mol % to 20 mol % TiO.sub.2; and 0 mol % to 25 mol % R.sub.2O, such that R.sub.2O is the sum of Na.sub.2O, K.sub.2O, Li.sub.2O, Rb.sub.2O, and Cs.sub.2O.

Disclosed herein are glass-ceramics having crystalline phases including -spodumene ss and either (i) pseudobrookite or (ii) vanadium or vanadium containing compounds so as to be colored and opaque glass-ceramics having coordinates, determined from total reflectancespecular includedmeasurements, in the CIELAB color space of the following ranges: L*=from about 20 to about 45; a*=from about 2 to about +2; and b*=from about 12 to about +1. Such CIELAB color space coordinates can be substantially uniform throughout the glass-ceramics. In each of the proceeding, -quartz ss can be substantially absent from the crystalline phases. If present, -quartz ss can be less than about 20 wt % or, alternatively, less than about 15 wt % of the crystalline phases. Also Further crystalline phases might include spinel ss (e.g., hercynite and/or gahnite-hercynite ss), rutile, magnesium zinc phosphate, or spinel ss (e.g., hercynite and/or gahnite-hercynite ss) and rutile.

Glass and glass ceramic compositions having a combination of lithium silicate and petalite crystalline phases along with methods of making the glass and glass ceramic compositions are described. The compositions are compatible with conventional rolling and float processes, are transparent or translucent, and have high mechanical strength and fracture resistance. Further, the compositions are able to be chemically tempered to even higher strength glass ceramics that are useful as large substrates in multiple applications.

Glass and glass ceramic compositions having a combination of lithium disilicate and -spodumene crystalline phases along with methods of making the glass and glass ceramic compositions are described. The compositions are compatible with conventional rolling and float processes and have high mechanical strength and fracture resistance. Further, the compositions are able to be chemically tempered to even higher strength glass ceramics that are useful as large substrates in multiple applications.

Crystallizable glasses, glass-ceramics, IXable glass-ceramics, and IX glass-ceramics are disclosed. The glass-ceramics exhibit -spodumene ss as the predominant crystalline phase. These glasses and glass-ceramics, in mole %, include: 60-75 SiO.sub.2; 10-18 Al.sub.2O.sub.3; 5-14 Li.sub.2O; and 4.5 B.sub.2O.sub.3. The glass-ceramics also have a Vickers initiation crack threshold of at least about 25 kgf.