Natural Stone Resources LIMOCEREF1224B-5SEPC 12" x 24" 5cm Ocean Reef Brushed Straight Edge Limestone 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 Ocean Reef Limestone Straight Coping is a beautiful choice. This coping provides a smooth surface and acts as a great finishing accent.