The hardness of bluestone is similar to that of red stone, except that bluestone is dense, pollution-free and radiation-free, and it will not smell when it meets water. Redstone generally has a faint smell when it meets water, and it has high water permeability and good bluestone effect, which will definitely be more expensive than ordinary redstone.
The stone trough is a concave stone pit, located in Zhukeng Ridge in the north of Sihaijian. Water flows through the wall to form a stone carving groove.