Celadon is a term for ceramics denoting both a type of glaze and a ware of celadon (color). Celadon originated in China, and later spread to other regions in Asia, such as Japan, Korea and Thailand. Celadon glazes can be produced in a variety of colors, including white, grey, blue and yellow, depending on several factors: 1) the thickness of the applied glaze, 2) the type of clay to which it is applied, and 3) the exact makeup of the glaze. However, the most famous shades range in color from a very pale green to deep intense green, often meaning to mimic the green shades of jade. The color is produced by iron oxide in the glaze recipe or clay body. Celadon are almost exclusively fired in a reducing atmosphere kiln as the chemical changes in the iron oxide which accompany depriving it of free oxygen are what produce the desired colors. As with most glazes, crazing (a glaze defect) can occur in the glaze and, if the characteristic is desirable, is referred to as "crackle" glaze. See "Celedon". Wikipedia. 2015-01-01.