Ashford Black Marble is a kind of dark limestone, which was mined from Ashford-in-the-Water, in Derbyshire, England. Once cut, turned and polished, its shiny black surface becomes very beautiful. Strictly speaking, Ashford Black Marble is not a marble formed by heat, but a smooth sedimentary rock, a hard mass of dusty minerals. To make art objects, Ashford Black Marble can be cut as materials of them and put together with other fine stones. Derby Museum has a diagram of Ecton Hill made from Ashford Black Marble and other minerals.