Sites listed here will offer information on the art and craft of working primarily with Stoneware. Sites will be non-commercial and may include artists' portfolios and galleries, studios, education and resources. Stoneware is a category of clay and a type of ceramic distinguished primarily by its firing and maturation temperature (from about 1200°C to 1315 °C). It is usually coloured grey or brownish because of impurities in the clay used for its manufacture, and is normally glazed". Pottery (i.e. made from clay) which has been fired at a higher temperature than earthenware. The temperature is high enough to partially vitrify the materials and make the ware impervious to liquids even when unglazed.