Ceramics is a collective term for all products that are made of clay, and is divided into earthenware, stoneware and porcelain. The distinction is determined by the various raw materials and the firing temperature. Clay, the main raw material of ceramics, is created by erosion and in its pure form contains a high percentage of the mineral kaolin. The purest form is used for the production of porcelain. Due to the high proportion of kaolin, the baked clay has a dense structure and very low porosity. Porcelain is fired at a temperature of between 1300 and 1400°C and is therefore the hardest type of ceramics.