Ceramic - (ce.ram.ic): any of various hard materials
made by firing a non-metallic mineral, as clay.

Almost all quality dinnerware produced today is made from either glass or ceramic coated with a glass like glaze.

The common grades of ceramic used for modern tableware are Earthenware, Stoneware and Porcelain. Each grade of ceramic is distinguished by the quality and purity of the clay used to form the product and the firing temperature reached in the kiln to harden the product.

The U.S. customs department classifies ceramic tableware based on two tests: water absorption and light translucency. Generally speaking, lower firing temperatures can be equated with less density, less resistance to water permeation, and less resistance to cracking and chipping. Practically speaking, both stoneware and porcelain are so dense and fired at high enough temperature (over 2,100 degrees Fahrenheit) that water permeation is not a problem, and both grades, being high-fired ceramics, are resistant to cracking and chipping.

The following section offers more information on each grade of ceramic:

Earthenware - any pottery body which, when fired, has a porosity of more than five percent. This usually means ware fired below 2,012 Fahrenheit. Due to the lower firing temperature, earthenware bodies are not as dense as a high-fired ceramic, have higher porosity, and are not as durable and resistant to chipping as a high-fired body. On the other hand, they are lighter in weight due to less density, and can be decorated with brighter-colored glazes, due to the lower firing temperatures. Due to its higher porosity, earthenware must be glazed in order to be water-resistant.

Stoneware - a hard, strong, vitrified ware, usually fired above 2,100 Fahrenheit, that contains a high percentage of clay (usually 90%) and a low percentage of non-clay materials. Due to the makeup of the clay and firing temperature, stoneware is a dense, strong, and durable ceramic that is especially appropriate for functional ware because it stands up well to constant use and frequent cleaning. Because of the high firing temperature vitrified stoneware and porcelain dinnerware is dishwasher and microwave safe.

Porcelain - true porcelains use a combination of pure white clay and an equal amount of non-clay material (silica and feldspars), are fired above 2,100 degrees Fahrenheit, and are translucent where thin. It is a very hard and dense ware after firing. Porcelaneous is a term used to refer to a grade of ceramic between stoneware and true porcelain that uses less non-clay material (about 30% versus 50% for true porcelains) and is commonly used for tableware. Porcelaneous may look like true porcelain, but is not translucent where thin. Both are high-fired, dense, hard, and very durable for everyday use.

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