The present invention relates to a chemically strengthened glass having a haze value in terms of a thickness of 0.7 mm of 0.5% or less, having a surface compressive stress value of 400 MPa or more, having a depth of a compressive stress layer of 70 μm or more, having an ST limit of 18000 MPa.Math.μm to 30000 MPa.Math.μm, and being a glass ceramic including at least one of a Li.sub.3PO.sub.4 crystal and a Li.sub.4SiO.sub.4 crystal, or including a solid solution crystal of Li.sub.3PO.sub.4 or Li.sub.4SiO.sub.4 or a solid solution of both Li.sub.3PO.sub.4 and Li.sub.4SiO.sub.4.

The present invention relates to a glass ceramic having a lithium aluminosilicate composition and including a crystal and a residual glass, in which the residual glass has a composition including, in terms of mol % based on oxides: 25% to 70% of SiO.sub.2; 3% to 35% of Al.sub.2O.sub.3; 0.1% to 20% of Li.sub.2O; 0.1% to 20% of Na.sub.2O; 0% to 10% of K.sub.2O; and 1% to 15% of ZrO.sub.2, and a parameter V is −600 or more and 720 or less, the parameter V being calculated based on the following formula: V=49.589×[SiO.sub.2]+61.806×[Al.sub.2O.sub.3]+45.456×[P.sub.2O.sub.5]+41.151×[MgO]+110.26×[CaO]+50.263×[SrO]+55.693×[Li.sub.2O]+3.598×[Na.sub.2O]+9.503×[K.sub.2O]+6.83×[TiO.sub.2]−2.885×[ZrO.sub.2]−3746.99.

A coated glass or glass ceramic substrate includes a substrate with a surface area and a coating on that surface area. The coating includes a glass matrix and IR-reflecting pigments. The IR-reflecting pigments have a TSR value of at least 20%, as determined according to ASTM G 173. The coating, at a wavelength of 1500 nm, exhibits a remission of at least 35%, as measured according to ISO 13468.

Embodiments of glass ceramic articles and precursor glasses are disclosed. In one or more embodiments, the glass-ceramic articles are transparent and include a nepheline phase and a phosphate phase. The glass-ceramic articles are colorless and exhibit a transmittance of about 70% or greater across the visible spectrum. The glass-ceramic articles may optionally include a lithium aluminosilicate phase. The crystals of the glass-ceramic articles may have a major cross-section of about 100 nm or less.

A heat-resistant synthetic jewelry material having a transparent, semitransparent or nontransparent composite nanocrystalline material on the basis of nanosized oxide and silicate crystalline phases. The material includes at least one of the following crystalline phases: spinel, quartz-like phases, sapphirine, enstatite, petalite-like phase, cordierite, willemite, zirconium, rutile, zirconium titanate, zirconium dioxide with a content of ions of transition elements, rare-earth elements and precious metals of from 0.001 to 4 mol %. One of the crystalline phases is additionally quartz-like solid solutions of lithium magnesium zinc aluminosilicates with a virgilite or keatite structure. The composition is selected from the following components,s SiO.sub.2, Al.sub.2O.sub.3, MgO, ZnO, Li.sub.2O, PbO, ZrO.sub.2, TiO.sub.2, NiO, CoO, CuO, Cr.sub.2O.sub.3, Bi.sub.2O.sub.3, Fe.sub.2O.sub.3, MnO.sub.2, CeO.sub.2, Nd.sub.2O.sub.3, Er.sub.2O.sub.3, Pr.sub.2O.sub.3 and Au.

A method of reworking lithium containing ion exchanged glass articles is provided. The method includes a reverse ion exchange process that returns the glass article to approximately the composition of the glass from which the glass article was produced, before being subjected to ion exchange. The reworked glass articles exhibit a K.sub.2O concentration profile comprising a portion wherein a K.sub.2O concentration increases to a local K.sub.2O concentration maximum.

Embodiments of glass ceramic articles and precursor glasses are disclosed. In one or more embodiments, the glass-ceramic articles are transparent and include a nepheline phase and a phosphate phase. The glass-ceramic articles are colorless and exhibit a transmittance of about 70% or greater across the visible spectrum. The glass-ceramic articles may optionally include a lithium aluminosilicate phase. The crystals of the glass-ceramic articles may have a major cross-section of about 100 nm or less.

A cover member includes at least a chemically strengthened glass. The chemically strengthened glass has a Young's modulus of 60 GPa or higher. The chemically strengthened glass includes a first surface and a second surface facing the first surface. The chemically strengthened glass has a thickness t of 0.4 mm or less.

Disclosed herein are opaque glass-ceramics comprising at least one nepheline crystal phase and comprising from about 30 mol % to about 65 mol % SiO.sub.2, from about 15 mol % to about 40 mol % Al.sub.2O.sub.3, from about 10 mol % to about 20 mol % (Na.sub.2O+K.sub.2O), and from about 1 mol % to about 10 mol % (ZnO+MgO). Also disclosed herein are opaque-glass ceramics comprising at least one nepheline crystal phase and at least one spinel-structure phase doped with at least one colorant chosen from transition metals and rare earth elements. Further disclosed herein are methods for making these opaque glass-ceramics.

Ion-exchanged glass ceramic articles described herein have a stress that decreases with increasing distance according to a substantially linear function from a depth of about 0.07t to a depth of about 0.26t from the outer surface of the ion-exchanged glass ceramic article from a compressive stress to a tensile stress. The stress transitions from the compressive stress to the tensile stress at a depth of from about 0.18t to about 0.25t from the outer surface of the ion-exchanged glass ceramic article. An absolute value of a maximum compressive stress at the outer surface of the ion-exchanged glass article is from 1.8 to 2.2 times an absolute value of a maximum central tension (CT) of the ion-exchanged glass article, and the glass ceramic article has a fracture toughness of 1 MPa√m or more as measured according to the double cantilever beam method.