Grey Sandstone

Graywacke sandstone is a sedimentary rock that is made up mostly of sand-size grains that were rapidly deposited very near the source rock from which they were weathered.In its purest form, sandstone is glassy and white in color, but the material is more typically found in shades of brown, yellow, red, and gray. The color of the rock is determined by the type of minerals it contains, as well as the characteristics of the material that bonds them together.