A decorative variety of the mineral fluorspar found in Derbyshire. It is translucent with bands of colour that range from deep purple through blue to light brown and yellow. Although known to the Romans, the first large deposit was found near Castleton in Derbyshire in 1743. It became popular for ornaments, especially in France. Matthew Boulton, the Birmingham metalwork manufacturer, used it for decorative objects with ormolu mounts, particularly candelabra.