The sandstone or arenite (sandstone whether as a stone) is a source of sedimentary rock composed of granules the size of a sand. The granules may composition varies, depending on the area of origin. Among the grains more abrasion resistant quartz remember that, precisely because of its strength, is one of the most common of these rocks. The granules are connected with each other by a cement that is commonly calcium carbonate, silica and iron oxide. The material that is usually found among granules called matrix, but when this material is crystallized is called cement.