abstract architecture backdrop background broken brown building construction contrast cover covering crushed decoration grain grains granular gravel grit gritty grunge grungy masonry material mica Mineral mortar natural nature orange pebble pebbles plaster protection quartz render Rendered rendering rock rough sand sandstone stone structure surface texture textured wall wallpaper weathered appearance colored coloring colors coloured colouring colours conglomerate contours contrasts cracks fissures flaws layered layers levels light lines rock-face rockface rocky rugged shade shadows shape shapes silicate strata stratum sunlight sunny sunshine surfaces textures veins