cobbles stone, slab stone, tumbled stone, key stones
Grey - Sandstone
Sandstone is basically a sedimentary rock which is primarily composed of tiny minerals or rock grains. A majority of sandstones are composed of minerals like quartz and feldspar which are present in the earths crust in abundance. The common constituents of sand are quartz and feldspar. The sand may also consists of organic matter or rock fragments.
Morecobbles stone, slab stone, tumbled stone, key stones