Monday, October 19, 2009

ceramics 101: k is for kaolin, p is for porcelain

Kaolin, also called "china clay", is a soft white clay that is an essential ingredient in the manufacture of porcelain. It is named after the hill in China (Kao-ling) from which it was mined for centuries. Samples of kaolin were first sent to Europe by a French Jesuit missionary around 1700 as examples of the materials used by the Chinese in the manufacture of porcelain.

Porcelain, also called "china" due its origins in that country, differentiates itself from earthenware and stoneware by its white color, its nonporous surface, its strength and, when very thin, its translucency. Porcelain is a mix of kaolin and feldspar, which vitrifies (becomes glass-like and water proof) at a high temperature, around 2280_F to 2640_F. Depending on the type of kaolin used, the color of the porcelain will vary from a creamy-white, to a cool-white, and the final piece will have a bell-like ring when struck.

I prefer using porcelain because of its soft and sensual feel when fired to a high temperature. On many of my pieces, I leave the outside unglazed, so the material's smooth surface can be appreciated with each use.

The above letters K and P are created by Jessica Hische and posted on her Daily Drop Cap blog.