Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a compressive stress CS (MPa) on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and DOL50%/DOLzero is 0.30 or more, where DOL50% (?m) is a depth at which the value of the compressive stress is 50% of the CS and DOLzero (?m) is a depth at which the value of the compressive stress is 0 MPa.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOLzero, which is a product of the compressive stress CS on the outermost surface and the stress depth DOLzero (?m), is 4.8×104 or more.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which, CS is 400 to 1400 MPa and CT×(T?2×DOLzero)/CS×DOLzero is 0.60 or more, where CS (MPa) denotes a compressive stress on an outermost surface of the compressive stress layer, DOLzero (?m) denotes a stress depth of the compressive stress layer at which the compressive stress is 0 MPa, CT (MPa) denotes a central stress determined by curve analysis, and T (?m) denotes a thickness of the substrate.

Abstract: Provided is a crystallized glass substrate including a surface with a compressive stress layer, in which a gradient A of a surface compressive stress from an outermost surface to a depth of 6 ?m in the compressive stress layer is 50.0 to 110.0 MPa/?m, a gradient B of a surface compressive stress from a depth of (a stress depth DOLzero—10 ?m) to the stress depth DOLzero is 2.5 to 15.0 MPa/?m, where the stress depth DOLzero is a depth of the compressive stress layer at a surface compressive stress of 0 MPa, and a hardness of the outermost surface at an indentation depth of 20 nm is 7.50 to 9.50 GPa.

Abstract: To obtain a crystallized glass member having a curved shape and provide a method for producing the same. A method for producing a crystallized glass member having a curved shape, including a deformation step for adjusting the temperature of a plate glass to a first temperature zone from higher than [At+40]° C. to [At+146]° C. or lower, where At is the yield point (° C.) of the plate glass and deforming at least part of the plate glass into a curved shape by external force acting on the plate glass while precipitating crystals from the plate glass.

Abstract: Provided is an inorganic composition article that is hard and highly transparent. The inorganic composition article includes at least one type selected from ?-cristobalite and an ?-cristobalite solid solution as a main crystal phase, has a coloring degree ?80 of 330 to 580 nm at a thickness of 10 mm, and has a Vickers hardness of 620 or more.

Abstract: To provide an inorganic composition article containing at least one kind selected from ?-cristobalite and ?-cristobalite solid solution as a main crystal phase, in which by mass % in terms of oxide, a content of a SiO2 component is 50.0% to 75.0%, a content of a Li2O component is 3.0% to 10.0%, a content of an Al2O3 component is 5.0% or more and less than 15.0%, and a total content of the Al2O3 component and a ZrO2 component is 10.0% or more, and a surface compressive stress value is 600 MPa or more.

Abstract: Provided are crystallized glass that is easy to process and in which a high compressive stress value can be obtained on a surface, and reinforced crystallized glass thereof. A crystallized glass containing at least one type selected from ?-cristobalite and an ?-cristobalite solid solution as a main crystal phase, in which, by mass % in terms of oxide, a content of a SiO2 component is 50.0% to 75.0%, a content of a Li2O component is 3.0% to 10.0%, a content of an Al2O3 component is 5.0% or more and less than 15.0%, and a content of a B2O3 component is more than 0% and 10.0% or less.

Abstract: Glass and crystallized glass of the glass, the glass containing, by mass% in terms of an oxide, 40.0 to 55.0% of a SiO2 component, 10.0 to 30.0% of an Al2O3 component, 10.0 to 30.0% of an MgO component, 5.0 to 15.0% of a TiO2 component, and more than 0 to 8.0% of an Na2O component.

Abstract: Provided is reinforced crystallized glass that has a high strength and is less likely to break. The reinforced crystallized glass includes a compressive stress layer on a surface, and [CS50 ?m*(DOLzero?50)]/2 is 2000 or more, where CS50 ?m (MPa) is a compressive stress at a depth of 50 ?m from an outermost surface, and DOLzero (?m) is a stress depth when the compressive stress is 0 MPa.

Abstract: Reinforced crystallized glass characterized including crystallized glass as a base material, the crystallized glass containing, as expressed in terms of mol % on an oxide basis, 30.0% to 70.0% of an SiO2 component, 8.0% to 25.0% of an Al2O3 component, 2.0% to 25.0% of an Na2O component, 1.0% to 6.0% of an Li2O component, 0 % to 25.0% of an MgO component, 0% to 30.0% of a ZnO component, and 0% to 10.0% of a TiO2 component, in which a surface of the reinforced crystallized glass is formed with a compressive stress layer, and a depth (DOLzero) of the compressive stress layer is 60 ?m or more.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOLzero, which is a product of the compressive stress CS on the outermost surface and the stress depth DOLzero (?m), is 4.8×104 or more.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, in which a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and CS×DOLzero, which is a product of the compressive stress CS on the outermost surface and the stress depth DOLzero (?m), is 4.8×104 or more.

Abstract: To provide a crystallized glass substrate including a surface with a compressive stress layer, where a stress depth DOLzero of the compressive stress layer, at which the compressive stress is 0 MPa, is 45 to 200 ?m, a compressive stress CS on an outermost surface of the compressive stress layer is 400 to 1400 MPa, and a central stress CT determined by using curve analysis is 55 to 300 MPa.

Abstract: A glass ceramic for an optical filter and an optical filter are obtained that have both thermal expansion characteristics for preventing refractive index fluctuations at a usage temperature of a filter member and mechanical characteristics considering durability, and further have excellent workability. An internal transmittance of the glass ceramic for an optical filter is 0.970 or more with respect to light having a wavelength of 1550 nm when a thickness of the glass ceramic is 1 mm. The glass ceramic includes, by mass % in terms of oxide, 40.0% to 70.0% of a SiO2 component, 11.0% to 25.0% of an Al2O3 component, 5.0% to 19.0% of a Na2O component, 0% to 9.0% of a K2O component, 1.0% to 18.0% of one or more components selected from a MgO component and a ZnO component, 0% to 3.0% of a CaO component, and 0.5% to 12.0% of a TiO2 component.

Abstract: Crystallized glass and strengthened crystallized glass with a novel composition, which have a high refractive index and high hardness, are provided. A crystallized glass, including, by mass % in terms of oxide, 20.0% or more and less than 40.0% of a SiO2 component, more than 0% and 20.0% or less of a Rn2O component, where Rn is one or more selected from Li, Na, and K, 7.0% to 25.0% of an Al2O3 component, 0% to 25.0% of a MgO component, 0% to 45.0% of a ZnO component, and 0% to 20.0% of a Ta2O5 component, in which a total amount of the MgO component, the ZnO component, and the Ta2O5 component is 10.0% or more.

Abstract: To provide an inorganic composition article containing at least one kind selected from ?-cristobalite and ?-cristobalite solid solution as a main crystal phase, in which by mass % in terms of oxide, a content of a SiO2 component is 50.0% to 75.0%, a content of a Li2O component is 3.0% to 10.0%, a content of an Al2O3 component is 5.0% or more and less than 15.0%, and a total content of the Al2O3 component and a ZrO2 component is 10.0% or more, and a surface compressive stress value is 600 MPa or more.

Abstract: To provide an inorganic composition article containing at least one kind selected from ?-cristobalite and ?-cristobalite solid solution as a main crystal phase, in which by mass % in terms of oxide, a content of a SiO2 component is 50.0% to 75.0%, a content of a Li2O component is 3.0% to 10.0%, a content of an Al2O3 component is 5.0% or more and less than 15.0%, and a total content of the Al2O3 component and a ZrO2 component is 10.0% or more, and a surface compressive stress value is 600 MPa or more.