Silica is one of the cornerstone materials of glaze and clay body formulation. Although this mineral is present in many different ceramic materials (from feldspars to bentonite to sand, for example), this silica is a pure version in a 200-mesh particle size.
As for silica's function in clay and glazes, it provides the melting, or glass forming agents in a clay body that allow the material to fuse together. Silica has a fairly high melting point, so it often needs to be fluxed with the addition of other materials that cause it to melt at lower temperatures. Silica imparts hardness to glazes, and decreases thermal expansion. In clay bodies, the expansion factor is exactly the opposite, an increased presence of silica increases the thermal expansion.
Chemical Formula: SiO2
Synonyms: Flint, Quartz