Do not warm them on the stove. Crazing The term 'crazing' means tiny hairline cracks in the glaze, not in the body of the ware. The glaze is put on to enhance the pattern and make the dishes more attractive but it is also there to protect the body of the ware, which is porous. When this crackling of the glaze has occurred, then moisture can get under the glaze and discolor the body of the ware. This crazing does not affect the value of many art pottery items but it does affect the value, usability and attractiveness of dinnerware pieces.
Earthenware is particularly prone to crazing but it does occur in china wares as well.
Dishwasher Wear Dishwasher damage occurs when items have been exposed repeatedly to high temperatures and harsh detergents. The glaze becomes thinner, dull and sometimes opalescent in color. Once this damage has occurred, it cannot be repaired. Types of Dinnerware Pottery Pottery is made from crude clay that is hardened by firing at a relatively low temperature in a kiln. It is usually less expensive than other ceramic products and lends itself to colorful, informal decorations.