Biogenic Silica: A Model of Amorphous Structure Control

Silicon is the second most abundant element in the Earth’s crust and in combination with oxygen the silicates form the largest and most abundant group of minerals. Many silicates are also formed in combination with other elements such as magnesium, aluminium, calcium and iron and as such form many of the minerals in our rocks and soils. Weathering processes over millions of years have also resulted in the occurrence of silica (silicon dioxide) in a variety of largely crystalline forms. The only naturally occurring amorphous silica mineral is opal.