In the majority of silicon dioxides, the silicon atom shows tetrahedral coordination, with four oxygen atoms … See more

SiO2 is most commonly encountered in nature as quartz, which comprises more than 10% by mass of the Earth's crust. Quartz is the only polymorph of silica stable at the Earth's surface. Metastable occurrence… See more

About 95% of the commercial use of silicon dioxide (sand) is in the construction industry, e.g. in the production of concrete (Portland cement concrete).
Certain deposits of silica sand, with desirable pa… See more

Silicon dioxide is a relatively inert material (hence its widespread occurrence as a mineral). Silica is often used as inert containers for chemical reactions. At high temperatures, it is converted to silicon by reduction wi… See more

Silica ingested orally is essentially nontoxic, with an LD50 of 5000 mg/kg (5 g/kg). A 2008 study following subjects for 15 years found that higher levels of silica in water appeared to decrease the risk of dementia. An increase … See more