High Quality Content by WIKIPEDIA articles! The chemical compound silicon dioxide, also known as silica (from the Latin silex), is an oxide of silicon with a chemical formula of SiO2 and has been known for its hardness since antiquity. Silica is most commonly found in nature as sand or quartz, as well as in the cell walls of diatoms. Silica is the most abundant mineral in the Earth's crust. Silica is manufactured in several forms including glass, crystal, gel, aerogel, fumed silica (or pyrogenic silica), and colloidal silica (e.g. Aerosil). In addition, Silica NanospringsTM are produced by the vapor-liquid-solid method at temperatures as low as room temperature.