Ceramic & glass

While the earliest ceramics were pottery, the term encompasses a large group of materials, including some pure elements. A ceramic is an inorganic, nonmetallic solid, generally based on an oxide, nitride, boride, or carbide, that is fired at a high temperature. Ceramics may be glazed prior to firing to produce a coating that reduces porosity and has a smooth, often colored surface. Many ceramics contain a mixture of ionic and covalent bonds between atoms. The resulting material may be crystalline, semi-crystalline, or vitreous. Amorphous materials with similar composition are generally termed "glass".