DSF Refractories and Minerals Limited (formerly Derbyshire Silica Firebrick Co Ltd) is the last major British producer of refractory products, both shaped and unshaped. DSF is located in Friden within the Derbyshire's Peak National Park. DSF also a processor and supplier of crushed and graded refractory raw materials for other applications such as coloured road-stone. By the 1960s, the business diversified into supplying other industries including steel, glass and cement.