Grey marble namely the Yunnan marble, also called "the Yunnan stone" or "the agate", "the dark green stone", is the famous stone of Diancang mountain in Yunnan whose chemical composition is the carbonic acid gray matter crystal. The color of gray marble may divided into the white and the multicolor two kinds approximately. Besides manufacturing in stone covering, also in the furniture decoration, like table boards, the chair back cushion, cabinet shutter crustification and so on. Gray marble plays the role which one kind added the finishing touch.