Base sands
Foundry sands and molding materials

Numerous basic sands are now available. While silica, by far the most widely used, is of natural origin, others are more or less artificial products which, because of their cost, are reserved for special uses.

• Lasilica, with the formula SiO ₂ , and more specifically its allotropic variety, α-quartz, is extremely widespread throughout the world in basins of sedimentary origin.

The main French deposits are located in the Paris Basin; Belgium, the Netherlands, the Federal Republic of Germany and the UK are also well supplied.

As a rough guide, annual consumption by the French foundry industry is around 1 million...