Sandstone is a type of rock composed chiefly of sand that has been "cemented" together by pressure or by minerals. The sand commonly consists of grains of quartz, feldspar, and other minerals. It may also include organic matter or rock fragments. The minerals that cement the grains include quartz, pyrite, or calcite. The color of sandstone ranges from cream or gray to red, brown, or green, depending on the cements and impurities in the sand.