In embodiments, a glass-ceramic article includes from about 55 wt. % to about 80 wt. % SiO.sub.2; from about 2 wt. % to about 20 wt. % Al.sub.2O.sub.3; from about 5 wt. % to about 20 wt. % Li.sub.2O; a non-zero amount of P.sub.2O.sub.5 less than or equal to 6 wt. %; and from about 3 wt. % to less than 8 wt. % ZrO.sub.2. The glass-ceramic grains having a longest dimension of less than 100 nm.

Disclosed herein are glass-ceramic compositions, articles made from the disclosed glass-ceramic compositions, and methods of making the same. More specifically disclosed herein is a glass-ceramic composition comprising: a) from about 2 mol % to about 20 mol % of Al.sub.2O.sub.3; b) from about 2 mol % to about 45 mol % of Li.sub.2O; and c) from about 48 mol % to about 80 mol % of SiO.sub.2; having a β-spodumene phase and a lithium silicate crystalline phase, and optionally a petalite phase.

The glass ceramic material of the present disclosure contains a glass that contains SiO.sub.2, B.sub.2O.sub.3, Al.sub.2O.sub.3, and M.sub.2O, where M is an alkali metal, and a filler that contains quartz, Al.sub.2O.sub.3, and ZrO.sub.2. The glass ceramic material contains the glass in an amount of 57.4% by weight or more and 67.4% by weight or less, the quartz in the filler in an amount of 29% by weight or more and 39% by weight or less, the Al.sub.2O.sub.3 in the filler in an amount of 1.8% by weight or more and 5% by weight or less, and the ZrO.sub.2 in the filler in an amount of 0.3% by weight or more and 1.8% by weight or less.

A transparent glass-ceramic composition including: of the formula Ta.sub.2-xAl.sub.xO.sub.5-x where x is less than 1; of the formula AlTaO.sub.4; of the formula AlPO.sub.4; a mixture of AlTaO.sub.4 and AlPO.sub.4; or a mixture of the formula Ta.sub.2-xAl.sub.xO.sub.5-x, AlTaO.sub.4, and AlPO.sub.4. Also disclosed are transparent glass-ceramic compositions including, for example, a dopant as defined herein, or a supplemental metal oxide or metalloid oxide of M.sub.xO.sub.y, M.sub.xM′.sub.xO.sub.y, or a mixture thereof such as oxides of Nb, Ti, W, B, or Ga, as defined herein. Also disclosed are methods of making the disclosed transparent glass-ceramic compositions, and optical articles, optical components, and optical apparatus thereof.

Al.sub.2O.sub.3-rich compositions with desirable hardness and crack resistance for various functional applications. Also disclosed is a method of manufacturing the composition into various dimensions and shapes under a temperature much lower than in conventional methods.

A glass-ceramic comprising, in weight percent on an oxide basis, of 50 to 70% SiO.sub.2, 0 to 20% Al.sub.2O.sub.3, 12 to 23% MgO, 0 to 4% Li.sub.2O, 0 to 10% Na.sub.2O, 0 to 10% K.sub.2O, 0 to 5% ZrO.sub.2, and 2 to 12% F, wherein the predominant crystalline phase of said glass-ceramic is a trisilicic mica, a tetrasilicic mica, or a mica solid solution between trisilicic and tetrasilicic, and wherein the total of Na.sub.2O+Li.sub.2O is at least 2 wt. %; wherein the glass-ceramic can be ion-exchanged.

Devices, apparatuses, and methods are disclosed that include a glass or glass ceramic substrate with a bleached region and an unbleached region. Examples include a substrate with a region that transmits IR wavelength light, and a region that is substantially opaque to IR light. Examples include additional opacity in some or all regions to visible wavelength light and/or UV wavelength light.

The present invention relates to a glass ceramic having a three-dimensional shape including plural R-shapes including a smallest R-shape whose average radius of curvature is 5.0×10.sup.2 mm or less and a largest R-shape whose average radius of curvature is 1.0×10.sup.3 mm or more, having a maximum value of retardations of 20 nm/mm or less, and having a haze value converted into a value corresponding to a thickness of 0.8 mm of 1.0% or less in the largest R-shape.

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.

A transparent glass-ceramic composition including: of the formula Ta.sub.2-xAl.sub.xO.sub.5-x where x is less than 1; of the formula AlTaO.sub.4; of the formula AlPO.sub.4; a mixture of AlTaO.sub.4 and AlPO.sub.4; or a mixture of the formula Ta.sub.2-xAl.sub.xO.sub.5-x, AlTaO.sub.4, and AlPO.sub.4. Also disclosed are transparent glass-ceramic compositions including, for example, a dopant as defined herein, or a supplemental metal oxide or metalloid oxide of M.sub.xO.sub.y, M.sub.xM′.sub.x′O.sub.y, or a mixture thereof such as oxides of Nb, Ti, W, B, or Ga, as defined herein. Also disclosed are methods of making the disclosed transparent glass-ceramic compositions, and optical articles, optical components, and optical apparatus thereof.