sandstones are sedimentary rocks known for porosity & hardnesss and are composed of small grains of quartz and feldspar. natural sandstones are often used as building stones. the natural red sandstone are extremely hard and tough material and consist of consolidated masses of sand deposited by moving water or by wind. the various colors of rocks are largely determined by the cementing material the iron oxides produce red or reddish-brown sandstone and the other materials produce natural sandstone in white, grayish or yellowish sandstone.