Translations:Benutzer:Arian/Klett-Mini-Test/802/en

Clay is a mixture of various clay minerals together with the amorphous end-products of weathering — the hydroxides of silicon, aluminium, iron, and so on. These latter are colloidal in nature, formless: a condition between solid and liquid, the very same condition that underlies all processual activity in the living. The plasticity of clay derives from its affinity to water, as well as from the partly submicroscopic smallness of the crystalline clay-mineral platelets, from the swelling capacity of certain clay-mineral types (*Montmorillonite* and others), and from the high water-absorbing capacity of the soil colloids. Water makes clay swell. The withdrawal of water through drying generates the finest shrinkage cracks, right down to deep fissures in the soil.