Know how to use "fewer" and "less"? Find out.
refractory material consisting of nonmetallic minerals formed in a variety of shapes for use at high temperatures, particularly in structures for metallurgical operations and glass manufacturing. Principal raw materials for firebrick include fireclays, mainly hydrated aluminum silicates; minerals of high aluminum oxide content, such as bauxite, diaspore, and kyanite; sources of silica, including sand and quartzite; magnesia minerals, magnesite, dolomite, forsterite, and olivine; chromite, a solid solution of chromic oxide with the oxides of aluminum, iron, and magnesium; carbon as graphite or coke; and vermiculite mica. Minor raw materials are zirconia, zircon, thoria, beryllia, titania, and ceria, and other minerals containing rare-earth elements