Moki Marble

SANDSTONE is a sedimentary rock composed of sand-sized grains of quartz and feldspar.The spaces between grains may be empty or filled with either a chemical cement of silica or calcium carbonate or a fine-grained matrix of silt and clay particles. Sandstones often form in layers in environments where large amounts of sands can accumulate such as beaches, deserts, flood plains, and deltas.

Sandstones are often used as building stones, and have importance to geologists as indicators of erosional and depositional processes.