Cushion sand is a native, general-purpose sand that is commonly used as a base for concrete work, laying pipes, leveling or building up areas to bring them up to grade. Cushion sand is a combination of clay and silt particles and packs very well compared to washed sands. Because the sand is dug deep, it does not typically contain weed seed sand can be used as a great amendment when blended with compost and other organic materials.