While at a museum recently, I stopped to admire a rare Parian pitcher. Manufactured in the 19th century by Vermont's United States Pottery Company (a forerunner of Bennington Potters), the piece was the only known version of their popular Niagara Falls pitcher done in color.

Looking at the label, I wondered how many individuals knew what Parian pottery was, and that led to ruminations about pottery in general. There are many different types of pottery, and if engaged in selling or collecting pottery, it's advantageous to be accurate in your descriptions. (And I don't know about you, but I often find such information interesting in its own right.)

Ceramic is the general term, referring to any non-metallic object that has been made by subjecting an inorganic material, like clay, to heat. Ceramic materials can be divided into three main groups: pottery, glass, and refractory materials (used in industry and manufacturing). Pottery and Glass are distinguished by their molecular structures: pottery has a crystalline structure, while glass does not. Glass flows, though at an imperceptible pace!

Regarding pottery, there are three major types: Porcelain, Earthenware, and Stoneware.

Earthenware is usually made of baked clay and must be glazed to make it impervious to liquids (i.e., it is non-vitreous). Terracotta is earthenware that has not been glazed, while Majolica and Creamware are just two of the many types of glazed earthenware.

Stoneware is a hard, vitreous ceramic, like porcelain, but is generally opaque, like earthenware. Wedgwood's Jasper Ware is one of the better-known examples of stoneware.

Of the three types of pottery, porcelain most resembles glass - it's hard, fine-grained, impervious to liquids, and usually translucent. Porcelain can be further classified according to material composition. Hard-paste, often called "true" porcelain, is made from a mixture of kaolin (China clay) and petuntse (a rock containing feldspar). It is generally hard, white, and translucent.

Soft-paste is a blend of fine clay and "frit," a glassy mixture. Though not as hard as hard-paste, it often has a "creamy" appearance and a softer decorated glaze effect that appeals to many collectors.

Bone China is porcelain to which bone ash has been added. It is usually considered less hard than hard-paste, but more translucent than soft-paste.

And Parian pottery? Parian is porcelain that resembles the white marble mined on the island of Paros by the ancient Greeks.

There are, of course, many more terms associated with pottery, and if you'd like to learn more about this interesting topic, check out the resources listed below:

Books

Illustrated Dictionary of Ceramics

The Potter's Dictionary of Materials and Techniques, Fifth Edition

Ten Thousand Years of Pottery

Websites

History of Chinese Ceramics - Link - Chalre Associates' site offers a look at various categories of Chinese ceramics. Lots of info and pics.

History of Porcelain - Link - Nicely written article.

An Introduction to Porcelain - Link - Helpful page at About Limoges Boxes offers a number of tips on differentiating hard- and soft-paste objects.

Types of Pottery - Link - This section of thepotteries.org is one of the more informative on this topic.