Cristobalite is a high-temperature crystalline polymorph of silica (SiO₂), crystallizing in the tetragonal system (low-temperature α-cristobalite) or cubic system (high-temperature β-cristobalite).It appears as colorless, white, pale yellow or light gray solid, usually in the form of octahedra, spherulites or powder, with a glassy luster and a Mohs hardness of 6–7.It is chemically very stable and only reacts with hydrofluoric acid and hot concentrated strong alkalis.

1. Refractory materials: Used in silica bricks, high-temperature ceramics and precision casting cores to improve refractoriness and thermal stability.
2. Optics / Electronics: Used in the manufacture of optical glass, optical fibers and semiconductor packaging materials.
3. Coatings / Plastics: Used as a functional filler for hardness enhancement, wear resistance and matting.
4. Dental materials: Component of alginate impression materials and dental models.
5. Chemical raw materials: Used for the preparation of elemental silicon, water glass, carborundum and other silicides.