Stoneware pottery is produced from clay that is fired to a dense, hard, vitreous state at a temperature of over 2300 degrees Fahrenheit. When stoneware is fired in kilns that burn gas flames come in contact with the ware. Reducing or increasing the amount of oxygen entering the kiln allows the artist to control the atmosphere of the kiln thus having a wide range of glaze effects. Stoneware is used for making functional, durable pots. It may be gray, buff or brown after the final firing. Stoneware pottery is food safe and will hold water.