Silica foundry glass refers to a high-purity form of silicon dioxide (SiO₂) used extensively in the foundry and casting industries. It is typically available in the form of silica sand, glass cullet (crushed glass pieces), or fused quartz. Owing to its superior thermal and physical characteristics, silica foundry glass is essential in the production of molds and cores for metal casting processes.

Its high melting point, chemical inertness, and low thermal expansion make it especially suitable for withstanding the extreme temperatures and chemical interactions involved in molten metal casting. These properties help ensure dimensional accuracy, structural integrity, and surface finish in the final cast components.