Natural clay that is white or pale-colored and sand-free is called kaolin or china clay.
Kaolin is mined from powdery layers, the result of age-long weathering of FELDSPAR, chemically, an aluminum silicate. Most white dishware is made from shaped, oven-fired kaolin.
Abundant deposits of kaolin occur from Delaware to Florida and in Washington state. Commoner clays are less useful than kaolin because they occur mixed with sand and discoloring minerals.