Petuntse

Petuntse (from 白墩子 in pinyin: bai2 dun1 zi0), also spelled petunse and bai dunzi, baidunzi, is a historic term for a wide range of micaceous or feldspathic rocks. However, all will have been subject to geological decomposition processes that result in a material which, after processing, is suitable as an ingredient in some ceramic formulations. The name means "little white bricks", referring to the form in which it was transported to the potteries (compare ball clay).

It was, and to some extent continues to be, an important raw material for Chinese porcelain, although the terms "porcelain stone", or "pottery stone", are now used. The equivalent term in Chinese is cishi.

It is mixed with kaolin in proportions varying according to the grade of porcelain to be produced; equal quantities for the best and two thirds petuntse to one third kaolin for everyday ware. There are large deposits of high quality stone in Jiangxi province in south-eastern China, which became a centre for porcelain production, especially in Jingdezhen ware.

While sharing some similarities to the material known as China stone, which is found uniquely in southwestern England, they differ in mineralogy. However both are derived from the alteration of igneous rocks.

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