The Collaborative International Dictionary
Petunse \Pe*tunse"\, Petuntse \Pe*tuntse"\, Petuntze \Pe*tuntze"\, n. [From Chinese.] Powdered fledspar, kaolin, or quartz, used in the manufacture of porcelain.
Wiktionary
n. (alternative form of petunse English)
Wikipedia
Petuntse (from 白墩子 in pinyin: bai2 dun1 zi0), also spelled petunse, 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.
It was, and to a limited extent continues to be, an important raw material for Chinese porcelain, although the term pottery stone is now used.
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.
Usage examples of "petuntse".
By putting the kaolin and the petuntse together in the right proportions, moulding the clay, and afterward applying to it a glaze of some sort the Chinese made their porcelain, and very beautiful porcelain it was.