Petuntse (白墩子 in pinyin: bai2 dun1 zi0), also spelled petunse, also known as china stone, is a granite-derived feldspar. It is one of the two ingredients used in making chinas[?] (the other ingredient being kaolin).
... or by a snap of the thumb, a person holding it in her hand can accelerate the gyroscope to incredibly high revs by following a circular wrist motion with the device. Modern ...