SANDSTONE     a sedimentary rock consisting usually of quartz, cemented with silica, iron oxide or calcium carbonate, Sandstone is durable, has a very high crushing and tensile strength and a wide range of colours and textures. Varieties of sandstone are commonly designated by the kind and prominence of interstitial and bonding material, as siliceous sandstone (bonding material primarily silica), calcareous sandstone (calcium carbonate prominent as bonding material or as accessory grains or both), sandstone (clay minerals prominent as interstitial or bonding materials, or as thin laminac ferruginous sandstone (iron oxide or hydroxide minerals (hematite,, limonite, et al) as interstitial or as boding materials in sufficient amount to impart appreciable colour of stone); brownstone (ferruginous sandstone of dark brown or reddish brown colour), arkose, arkosic sandstone, or feldspatic sandstone (a sandstone that contains an abundance of grains of feldspar), conglomerate a sandstone composed in large part of rounded pebbles, also called puddingstone).