mosaic is made of nature slate,Firstly, the slates are back gauged; Secondly, they are sawed into small pieces ,then the artisans beat the foursides of the small pieces in different shapes 5 sizes with high-0 epoxy.size: 30×20, 40×25 or per as clients's requirements5: first in carton then packed in wooden cratecolor: black, rusty green, oyster 5 mixed color