Sodium silicate received the name "water glass" from ancient alchemists because it takes the form of pieces of glass when dry, but it also dissolves in water to form a viscous liquid. Sodium oxide or sodium carbonate reacted with silica, which is sand, forms sodium silicate.
Sodium silicate is sold as a paste, or in liquid or dry form. The primary use of sodium silicate in industry is to repair items such as glass, or leaky engines where is it inserted in its liquid form and plugs the leaks after it dries. Other uses of sodium silicate include fireproofing paper, wood and cement, as a protective coating that fixes pigments to paintings, and as an additive in water treatment, petroleum processing and some detergents.
In the past, people used sodium silicate to store eggs for an extended period of time, a maximum of two years, by placing the eggs in a gelatinous mixture of water and sodium silicate powder sold by companies such as the Reliance Ink Company of Canada. The mixture inhibited the growth of bacteria on the eggs by stopping oxygen and moisture from permeating to the egg. However, people no longer store their eggs using this method as eggs are now widely available and not at risk of a shortage.