A stone shaped like a bark.

It is silicified wood, which is the product of asbestos substitution, that is, the trees keep their original shapes but the materials have turned into stones. It used to be popular for a while, and it was basically used for decoration. Later, it developed to polish its surface. Because the color is gray, it is easy to mistake it for jade, but it is still far from the structure of jade. It has a certain collection value, but it is currently in a tepid stage in the market.