Clays are fine-grained minerals found in sedimentary rocks which can be formed from decomposition of rocks due to the presence of water. There are various synonyms for this word; one of which is mud, which is commonly used to refer to a mixture of soil and water. Another synonym is clayey soil, a type of soil that is rich in clay particles and tends to be slow-draining. Other synonyms include kaolin, terra-cotta, and earthenware, which are different types of clays used in pottery and ceramics. Bentonite, ball clay, and fire clay are other types of clays used for industrial purposes like oil drilling and construction.