Natural Stone Resources SLTINDBLU2424G-5RFCC 24" x 24" 5cm Indian Bluestone Gauged Slate Chiseled Edge Column Cap. 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 Indian Bluestone Column Cap is a beautiful choice. A perfect finishing touch!