silicaSilicic acid is a weak acid that has been derived from silicon dioxide SiO2 of pure silica sand.
Silicate is obtained by melting quartz sand with potash (potassium carbonate, K2CO3) and soda (sodium carbonate, Na2CO3). It is a molten mass of glass that is soluble in water. The insolubility of glass is obtained by adding lime (calcium carbonate, CaCO3) or lead (II) oxide.