what is clay chemically
Clays and Clay Minerals. Clay is the common name for a number of fine-grained, earthy materials that become plastic when wet.Chemically, clays are hydrous aluminium silicates, usually containing minor amounts of impurities such as potassium, sodium, calcium, magnesium, or iron.One of the commonest processes of clay formation is the chemical decomposition of feldspar.he most abundant use of clay is in brick making. Granite is made up of quartz, mica and feldspar. As quartz is resistant to chemical weathering, it may be removed only as mineral grains of quartz. Feldspars and micas are susceptible to chemical weathering and break down to form clay minerals.