Aluminum oxide, commonly referred to as alumina, has the chemical formula Al2O3. Sapphire is the single crystal form of alumina, and is not only a gemstone of various colors, but a very durable and robust material for optical components. Corundum or α-alumina is the most common natural crystalline form of alumina.

Typical of many ceramics, alumina has low electrical conductivity and is considered an electrical insulator. Unlike many ceramics, alumina has a fairly high thermal conductivity and can be used as a heat sink. Alumina has high temperature capability and is chemically inert, which enables use in corrosive environments even at elevated temperature.

CeraNova has developed a high hardness, high strength, high temperature form of alumina called CeraLumina™ that is transparent in the infrared portion of the spectrum. CeraLumina is being used in applications where infrared transparency is required, and its superior mechanical properties are essential. In optical applications, high strength CeraLumina can be thinner than sapphire reducing adsorption losses. The high hardness of CeraLumina lends itself well to applications where scratch resistance and surface finish durability are vital. A non-transparent form of CeraLumina is also produced for applications where the mechanical properties are needed, but transparency is not required.