Additionally, it's a porous and ideal alternative to tarmac, therefore our Obsidian colour will allow water to drain through giving a huge advantage by reducing drainage costs. This striking black twinned with a stunning shine is perfect for both resin bound borders and full driveway systems. Rock Type: Basalt Rock Shape: Angular Slip Resistance (PTV): 80 Ideal For: Driveways, Paths & Patios Hardness Rating: 5 Overall Performance: 5
