This is the ceramic made of fireclay which is non-refractory by nature. Stoneware need to be bisque and fired in high temperature. There are a few variations of it, like traditional. Fine, chemical, thermal shock resistant, and electrical. The usage of these various kind of stoneware also have been different, like their names. Traditional stoneware are more common and opaque , while fine ones are used for art pieces and created more delicately.