CRYSTALLIZED GLASS, CRYSTALLIZED GLASS OF THREE-DIMENSIONAL SHAPE, AND PRODUCTION METHOD THEREFOR

The present invention relates to a glass ceramic having a three-dimensional shape including a plurality of round shapes including a minimum round shape having an average curvature radius of 5.0×102 mm or less and a maximum round shape having an average curvature radius of 1.0×103 mm or more, in which the glass ceramic has a sheet thickness t [mm], and a value obtained by dividing a maximum value of retardation [nm] measured by the following measurement method by the sheet thickness t [mm] is 50 [nm/mm] or less, measurement method: retardation is measured using a birefringence measuring device by vertically irradiating one or more points on an arc of each of the round shapes with light having a wavelength of 543 nm.