Category: Glaze, Clear, Author: Derek Au, Notes: From Nigel Wood's Chinese Glazes, page 263. Porcelain glaze, 1240-1290 degrees Celsius, oxidation or reduction. One of my favorite clear glazes. This could also be classified as a Celadon, as the impurities in the kaolin and ball clay will lend it a bit of color. In my experience, changing the types of kaolin and ball clay used will significantly alter the appearance.