These are imitation black stones for outdoor fireplaces or firepits. They are light weight ceramic fiber, gel cast and designed to take on outdoor elements. Each set comes with a 84 piece assortment of large & small stones (large pieces 4 1/2", small pieces 2 1/2"). One set is 1/2 cu. ft. (15 lbs). Shipping is free, however we ship only within the continental United States.