Derived from the Greek word keramos, ceramics means “burned clay.” Originally, the term was referred to china; nowadays, the term is also used for non-metallic, inorganic substances such as refractories, glass and cements as ceramics. For this reason, ceramics are now regarded as no-metallic, inorganic substances that are manufactured through a process of moulding and exposure to high temperatures.
Ceramics are divided into secondary categories: pottery, stoneware, earthenware and porcelain.
Conventional ceramics are made from natural materials such as clay and silica rock. Typical examples include china, fibrebricks, cements and glass. Ceramics are made by mixing, shaping and firing natural minerals including pottery stones, feldspar and clay.
What is pottery?
Commonly known as the art of making pots, ceramic ware or a potter’s studio, pottery is generally considered to be containers made from clay. Pottery includes glazed ceramics fired at higher temperatures than earthenware – between 1,000 – 1,250°C and has water absorption properties.
Made from clay, earthenware is not fired to the point of vitrification. Earthenware is made waterproof by the application of a liquid clay mixture applied before firing. For both practical and decorative reasons, earthenware is usually glazed. There are two main types of glazed earthenware. One is covered with a transparent lead glaze, which is cream in colour and thus called creamware. The second type is covered with an opaque white tin glaze and is known as tin-enamelled, tin-glazed, majolica, faience or delft.
A glaze allows potters to seal their pottery and is applied after the pot has gone through the firing process in the kiln for the first time. The first firing hardens the clay and only after the glaze is applied does the pottery gets placed in the kiln again. The glaze then melts and sticks to the pottery, providing protection and waterproof properties to the outside of the vessel.
