Natural Stone Resources LIMPURGRY1224D-5MEPC 12" x 24" 5cm Purbeck Gray Distressed Limestone Modern Edge Pool Coping. Natural Stone Resources is a premier importer & distributor of quality natural stones from around the world. Whether you're looking to add coping to your masonry walls, columns, landscape, steps, or pools, the Purbeck Grey Limestone Modern Coping is a beautiful choice. This coping provides a smooth surface and acts as a great finishing accent.