A ceramic is a nonmetallic, inorganic solid that, much like glass, is created through heating and subsequent cooling. A ceramic can even be a glass when they have an amorphous or non-crystalline structure. However, most ceramic materials have a crystalline or partly crystalline structure. The technical definition of ceramics is therefore typically limited to inorganic crystalline materials, in contrast to noncrystalline materials, which would be considered glasses. There are many different kinds of ceramic materials and are represented in diverse applications for nuclear fuel, porcelain, earthenware, ceramic goods, statuettes, ampoules, building tiles, superconductors, orbital entry heat shields, industrial heating elements, thermal processing and firing equipment, glazing, other refractory and insulation material applications, and ultrasonic transducers. Substances used in ceramics manufacturing are sourced from the mining and chemical industries to produce construction materials, consumer goods, and specialty industry and research materials and components.