The primary chemical component of sand is silica, followed by smaller amounts of alumina, iron oxide, and calcium oxide.
The chemical composition of sand is primarily SiO2, or silica. Silica, by definition, is a component of soil, rock, and other minerals.
The chemical composition of sand is required in order to determine its suitability of sand for various applications. For example, sand that is high in silica content is often used in glassmaking, while sand that is high in alumina content is used in the production of refractory materials.