What is silica sand

What is silica sand? Silica sand or quartz are the minerals of silica which is one of the optical crystal-forming minerals. Tetra hidron have one silicon atom surrounded by four oxygen atoms. It is an atomic structure of silica sand or that we are familiar with other silica. For example is Mg2SiO2 in MgSiO4 and SiO4 ions can be obtained four electrons from Mg atoms which gives one electron to the