Sand is a granular material composed of finely divided rock and mineral particles It is defined by size, being finer than gravel and coarser than silt Sand is a non-renewable resource over human timescales and sand suitable for making concrete is in high demand A stone is a piece of rock It is a mass of hard, compacted mineral The word stone also refers to natural rock as a material, especially a building material Natural stone used as building material include granite, marble and sandstone