Each cobble is 60-120mm Charcoal grey when dry before darkening to black when wet Ideal for creating a modern, contemporary space Popular in garden borders, raised beds, rockeries and gabion baskets A naturally rounded cobble which are charcoal when dry before darkening to almost ...Each cobble is 60-120mm Charcoal grey when dry before darkening to black when wet Ideal for creating a modern, contemporary space Popular in garden borders, raised beds, rockeries and gabion baskets A naturally rounded cobble which are charcoal when dry before darkening to almost black when wet, our Ebony Black Cobbles are ideal for creating a modern, contemporary space. Very popular in garden borders, raised beds and rockeries, their larger size also makes them perfect for use in our gabion baskets.