Stoneware is manufactured from clay, quartz, or minerals such as calcite and is defined as a group of ceramic products. Stoneware is used to produce, plates, dishes, cachpots and bowls, moulded at very high temperatures using special casting techniques. The high temperatures during the firing process make stoneware more stable than clay and less translucent than porcelain. The colours depend on the firing temperature and time. Therefore, each piece can show individual structures and shades. As stoneware is not watertight, it is often glazed.