19 Building and construction stone materials namely crushed and gravel aggregates, granite and limestone boulders, sandstone and limestone outcroppings, quarried stone slabs, cobblestone, building veneer stone, stone cut drywall, flagstone made up of fine-grained granite, sandstone, limestone, bluestone, quartzite, slate, flagstone steppers, sand, wallstone which may be of limestone, sandstone or bluestone, concrete and clay paving stone