An Frosterley marble bolection-moulded chimneypiece in the late 17th century style

Frosterley marble was quarried in a handful of locations in Weardale, County Durham. A rare and costly material, it was used in some of the finest historic buildings of Britain, notably York Minster, the cathedrals of Durham, St. Albans, Bristol and Norwich, as well as Agia Sophia in Bayswater - also for the pulpit in Bombay cathedral. It dates from the Lower Carboniferous period of the Palaeozoic era, some 320 to 350 million years ago. It contains well-spaced specimens of fossil corals (Dibunophyllum bipartitum), together with shell fragments, brachiopods as well as tree and leaf matter. It is the elegant internal structures of the corals which provide the delicate formations visible when it is cut and polished.