The mineral composition of silica bricks is generally mainly tridymite and cristobalite, including a small amount of quartz and glass. Tridymite, cristobalite, and residual quartz have large volume changes due to crystal form changes under the action of low temperature, so the thermal stability of silica bricks at low temperature is relatively poor. When used, it should be slowly heated and cooled to below 800 ℃ to avoid cracks and danger. Therefore, it is not suitable for furnaces with sudden temperature changes below 800 °C.

The working performance and use process of silica bricks are closely related to the crystal transformation of SiO2. Therefore, the proportion of SiO2 in silica bricks is an important quality indicator of silica bricks. The larger the proportion of SiO2, the better the performance of silica bricks. . The quality of silica bricks generally requires a true ratio below 2.38, and high-quality silica bricks should be below 2.35. The true specific gravity is small, reflecting that the amount of tridymite and cristobalite in the brick is large, and the amount of residual quartz is small, so the residual linear expansion is small, and the strength drop-in use is also small. Silica is available in seven crystalline variants and one amorphous variant. These variants can be divided into two main groups: the first variants are quartz, tridymite, and cristobalite, which have very different crystal structures and are slow to interconvert; the second variants are subspecies of the above variants - alpha beta and gamma types, their structures are similar, and the transformation speed between them is faster.

The raw material for making silica bricks is silica. The higher the SiO2 content of the silica raw material, the higher the refractoriness. The most harmful impurities are Al2O3, K2O, Na2O, etc., which seriously reduce the refractoriness of refractory products. Silica bricks are made of silica with a SiO2 content of not less than 96%, adding mineralizers (such as iron scale, lime milk) and binders (such as molasses, sulfite pulp waste liquid), and then kneading, molding, drying, and firing and other procedures.