Sandstone is sand turned to rock over time. It formed when grains of sand become cemented together. Sandstone is opaque, with a dull often rough luster. It is usually tan or yellowish, though can be found pink to dark red, and even sometimes blue and green Sandstone is identified by distinct wavy color or tone patterns from how the sand lawyered. Horizontal lines through the stone, indicating the layers, shows it is sandstone not limestone. Limestone is uniform in monochrome (one color). The hardness varies with sandstone but is often around 7. If you break a part off with a hammer it will crumble with lots of sand. Limestone doesn’t crumble.