WATER GLASS

also called Sodium Silicate, or Soluble Glass, crystal-like lumps that range from colourless to white or grayish white and resemble glass but can be dissolved in water to form a syrupy liquid. Some forms are slightly soluble, and some are almost insoluble; they are best dissolved by heating with water under pressure. A little water dissolves water glass more readily than much water does. The solutions are strongly alkaline. The chemical formulas Na2SiO3, Na6Si2O7, and Na2Si3O7 describe the composition of various forms of water glass. Water glass is used as a bonding agent in manufacturing grindstones and abrasive wheels. It is a cement for glass or porcelain and is used in various industrial and certain printing processes. It was formerly used as a household preservative for eggs.