Limescale is the hard, off-white, chalky deposit found in kettles, hot-water boilers and the inside of inadequately maintained hot-water central heating systems. It is also often found as a similar deposit on the inner surface of old pipes and other surfaces where hard water has evaporated. It consists of the salts of Calcium and Magnesium being preciptated when hard water ie: water with a high concentration of such salts, is heated or pressure changes. Effectively the dissolved salts in hard water come out of solution and preciptate back in their original form as solid crystals of Calcium Carbonate.
