Abstract: A cover glass is provided that includes a silica based glass ceramic with a thickness between 0.4 mm and 0.85 mm. The glass ceramic has a transmittance of more than 80% from 380 nm to 780 nm and a stress attribute selected from: an overall compressive stress (CS) of at least 250 MPa and at most 1500 MPa, a compressive stress at a depth of 30 ?m (CS30) from one of the two faces of at least 160 MPa and at most 525 MPa, a depth of the compression layer (DoCL) of at least 0.2 times the thickness and less than 0.5 times the thickness, and any combinations thereof. The glass ceramic has at least one silica based crystal phase having in a near-surface layer a unit cell volume of at least 1% by volume larger than that of a core where the crystal phase has minimum stresses.

Abstract: A cover glass made of a glass ceramic that is silica based and has a main crystal phase of high quartz solid solution or keatite solid solution is provided. The cover glass has a stress profile with at least one inflection point at a depth of the cover glass of more than 10 ?m, a thickness from 0.1 mm to 2 mm, and a chemical tempering structure with a surface compressive stress of at least 250 MPa and at most 1500 MPa. A process for producing the cover glass is provided that includes producing a silica based green glass, hot shaping the silica based green glass, thermally treating the silica based green glass with a nucleation step and a ceramization step, and performing an ion exchange at an exchange bath temperature for a duration of time in an exchange bath.

Abstract: A cover glass is provided that includes a silica based glass ceramic with a thickness between 0.4 mm and 0.85 mm. The glass ceramic has a transmittance of more than 80% from 380 nm to 780 nm and a stress attribute selected from: an overall compressive stress (CS) of at least 250 MPa and at most 1500 MPa, a compressive stress at a depth of 30 ?m (CS30) from one of the two faces of at least 160 MPa and at most 525 MPa, a depth of the compression layer (DoCL) of at least 0.2 times the thickness and less than 0.5 times the thickness, and any combinations thereof. The glass ceramic has at least one silica based crystal phase having in a near-surface layer a unit cell volume of at least 1% by volume larger than that of a core where the crystal phase has minimum stresses.