... customer's request 2.ISO9001:2000,ISO14001:2004 Sand rock is a type of high quality natural ... pollution or radiation hazard to human being.A.quarts over 52%;B.clay around 15%;C.goethite ... around 18%;D.miscellaneous over 10%Sand rock,sound insulation,misture absorption,no weathering outside, ... in water without moss and easy clean. Red Sand Rock1Size 300×200cm,300×100cm,200×100cm,30×30cm ...