Go stones are manufactured in chinese province Yunnan. The exact
composition and technology of its production, elaborated in the Ming
Dynasty, are kept strict secret. It is said that there are more than 40
ingredients which enter into the composition of Yunzi, including agate
Yunzi stones can be devided with regard to their shape, or color of white stones.
There are two types of Yunzi. Classic- flat on one side, conv..