Zircon is a zirconium silicate product that is used for a wide variety of applications. The majority of the zircon sold is used in a variety of high temperature applications. Zircon is a very hard refractory material resistant to chemical attack. Most of its applications rely on these special properties of zircon. Its main use is as an opacifier, giving ceramics an opaque white appearance. Because of its thermal and chemical resistance, zircon is also used in aggressive environments, such as the manufacture of moulds for casting molten metals.
Zirconium dioxide, which is referred to as zirconia, is derived from further processing of the zircon product and is used in laboratory crucibles, metallurgical furnaces and as a refractory material. It is also used to create speciality items like ceramic knifes. Stabilised zirconia, a particular form of zirconia, is used in oxygen sensors and fuel cell membranes because it has the ability to allow oxygen ions to move freely through the crystal structure at high temperatures. This unique property of high ionic conductivity and low electronic conductivity also makes it very useful in the field of electro-ceramics.