Silicon Dioxide or Silica is Quartz
Silicon dioxide also known as silica is a chemical compound made up of two of the most abundant chemical elements in Earth's crust, silicon (Si) and oxygen (O2). Made up of one atom of silicon and two atoms of oxygen its chemical formula is SiO2.
Silicon dioxide (oxide means 1 dioxide means 2) which is also known as silica is found most commonly in nature as the mineral quartz. It's present in most types of sand, exists in several different crystalline forms and a number of cryptocrystalline forms. In its purest form silicon dioxide is colourless and transparent but impurites cause a wide range of different colours.
Silicon dioxide is widely used in industry because its melting point is higher than copper, iron and aluminium. It's widely used for the production of glass, optical fibres and as a raw material in whiteware ceramics, stoneware, porcelain and industrial cement. It's also used in toothpaste because its hardness helps to remove plaque. As a food additive silicon dioxide protects dried foods from moisture and powdered foods from clumping or sticking together.
The small white packets called silica gel that can often be found with new merchandise contain grains of silicon dioxide. These absorb moisture hence protect the item they're packed with.