Ceramics are materials produced by treating non-metallic inorganic materials (originally clay) at high temperatures. Modern ceramics include such diverse products as porcelain and china, furnace bricks, electric insulators, ferrite magnets, rocket nose cones, and abrasives.
Porcelain is made from kaolin and feldspar, and heated to a high temperature. It is nonporous and translucent.
In general, ceramics are hard, chemically inert under most conditions, and can withstand high temperatures in industrial applications. Many are refractory metal oxides. Primitive ceramics in the form of pottery date from the 5th millennium BC, and improved steadily in quality and design. By the 10th century AD porcelain had been developed in China. See also cermets.