The molecular formula of silicon dioxide is SiO2, the molecular weight is 60.1, the density is 2.3~2.65g/cm³, the hardness is 7, and the melting point is 1713°C. It has good chemical and thermal stability and is almost insoluble in other acids except hydrofluoric acid.

The main function of SiO2 in enamel frit is to form the network skeleton of the spatial structure of the enamel. It can also improve the gloss of the porcelain surface, make the porcelain surface smooth and dense, and make the enamel have good chemical stability and wear resistance. At the same time, due to Its small expansion coefficient improves the thermal stability of enamel.

SiO2 has various variants at different temperatures, which will cause crystal changes due to temperature, resulting in changes in volume and specific gravity.

Due to the strong internal chemical bond of SiO2 molecules, it is not easy to break. Therefore, the melting temperature and firing temperature of enamel with high SiO2 content are higher than those of enamel with low SiO2 content.

There are many raw materials for introducing SiO2, mainly quartz sand, feldspar and other ore sands containing SiO2.