Pottery clay is a type of clay that is used to make pottery and other ceramic objects. It is usually composed of kaolinite, quartz, mica, and feldspar. Terracotta is a type of pottery clay that is made from a mixture of clay, sand, and water. It is often used to make decorative objects such as vases, sculptures, and tiles. Terracotta is also used in construction, for example in roof tiles and bricks.