Some notes on ceramics
Porcelain is clay which, when fired, becomes very hard and strong and usually translucent. Porcelain is normally very white and has a very smooth surface. Porcelain clays lack iron impurities and are ground to very fine particle sizes, which contributes to their higher density.
Stoneware is high fired ceramics often made of clays that are not highly refined. Stoneware can be brown, buff or white. Stoneware commonly has some specks and some particulate material such as sand or fine grog. Stoneware is vitreous or semi-vitreous, not translucent.
Earthenware is a clay fired at low temperatures where it does not become vitreous. Earthenware is porous and therefore not as strong as stoneware and porcelain. Earthenware glazes are usually very bright colored and if the glazes are properly chosen, earthenware can be quite strong and functional.
All ceramics have spots on them that are not glazed. During the firing process, the area that rests on the surface of the kiln remains bare. The most expensive ceramics sit on the points of little stands in a kiln, so that more of the surface will take the glaze; the spots are evident if you look closely or run your hand along the bottom.
Though porcelain can easily take the temperature and harsh detergents of a dishwasher, we recommend washing most of them by hand, to prevent accidental damage from other utensils beating against them in the dishwasher.
Because of the dense nature of porcelain, discoloration of bare spots can usually be cleaned with detergent and nylon scrubber.
On Capacity Indicated Below. For comparison purposes, capacity is listed at the maximum fill level, up to the rim. The practical capacity is usually less; on small utensils, like the soup bowls below, deduct 2-3 ounces from the capacity listed; on larger utensils, like soup tureens, deduct 1-2 cups or more from the capacity listed.