A type of marquetry, using tortoiseshell and brass. Originally an Italian process, it was perfected by André-Charles Boulle in France in the 18th century. It was produced by gluing together sheets of tortoiseshell and brass, which were then cut to the design using a fretwork technique. The layers could be combined to produce a tortoiseshell ground inlaid with brass (‘first-part’) or a brass ground inlaid with tortoiseshell (‘counter-part’). This could be used to great decorative effect on furniture. The brass was often engraved to provide greater richness. During the 19th century a machine-based process, ‘Buhl work’, was used to simulate this technique.
http://collections.vam.ac.uk/item/O58571/pedestal/ Description and illustration of boulle pedestal on Victoria and Albert Museum website.