Cristobalite is a high temperature modification of silica. In contrast to silica cristobalite is rarely existent in nature. Therefore cristobalite is made out of pure silica by heating it up to 1.500°C. Through this calcining-process the lattice is expanded and the density is reduced to 2.35 g/cm³. The thereby generated air bubbles lead to a negative refractive index and an outstanding brightness. Like silica cristobalite is chemically inert. Products from medium grain sizes from 300 µm down to micronized powders with only 1m are available.
