Silicon dioxide which is also known as silica, is the name of a compound made up of silicon and oxygen. Silica has one atom of silicon and two atoms of oxygen and is found most commonly in nature as quartz which is the second most abundant mineral in the Earth's crust. The most common ingredient in many types of sand is silica and it appears mostly in the form of quartz.
In industry, silicon dioxide or silica is used in the production of glass, optical fibres in telecommunications and it's one of the primary raw materials used in whiteware ceramics, stoneware, porcelain and industrial cement. Silicon dioxide is also manufactured for use in toothpaste because its hardness helps to remove plaque.