Definition: Bentonite (noun) is used in pottery both in clay bodies and in glazes. It is a highly plastic, sticky clay which is the result of decomposing volcanic ash or rock. In clay bodies, it promotes plasticity. In glazes, it can help raw glaze coats to adhere to bisqueware before firing, Bentonite also helps keep the particles of the liquid glaze batch in suspension.
Examples:
A little bentonite can go a long way.