Celadon is a term for ceramics denoting both wares glazed in the jade green celadon color, also known as greenware (the term specialists tend to use) and a type of transparent glaze, often with small cracks, that was first used on greenware, but later used on other porcelains. Celadon originated in China, and notable kilns such as the Longquan kiln in Zhejiang province are renowned for their celadon works. Celadon production later spread to other regions in Asia, such as Japan, Korea and Thailand. Finer pieces are in porcelain, but both the color and the glaze can be produced in earthenware.