Description Bluestone Gabion Walling Rocks, various sized blue random sized rocks that look great in the garden, as a feature or as a retaining wall. Colour and sizes vary so please visit our Hackham Yard to choose the rocks that best suit your requirements. Bluestone is sold by the tonne. Key Features of Bluestone Gabion Walling Rocks: Used as a feature in garden beds, for retaining and walling or in rockeries Sizes may vary, visit Hackham Yard to choose your desired rocks. Rubble Delivery: Rubble and metals are sold by the tonne, and are available online or in-store. Delivery across Adelaide starting from just $35.