Inlaying is the art of decorating flat surfaces by the insertion of materials differing from the ground or body in which they are inlaid, in colour, texture, or other qualities. The body or basis may be wood, stone, or metal, and the inlaid or encrusted substances may be woods of various colours, ivory, mother-of-pearl, tortoiseshell, precious and other metals, marbles, and hard and precious stones, all these substances being selected principally on account of the brilliance and variety of their colours. Inlaying in wood is known generally as marquetry; in metals the inlay principally practised is called Damascening (q.v.); and in marble and precious stones it forms a variety of Mosaic-work (q.v.). As is the case with most decorative arts, the origin of inlaying can be traced to eastern countries. While some kinds of inlays were known in ancient Rome, the art as practised in modern times first took root in Venice in the 15th century, when small caskets were ornamented with inlays of ivory and wood in strictly geometrical patterns, such as continue to be reproduced to this day in the familiar inlaid-work of Bombay. Contemporaneously the Florentines began to ornament furniture, &c. with small inlaid dice of ivory arranged to form various patterns, and this style of inlay has since become generally known as Certosa-work, from the fact that the choir-fittings in the church of the Certosa or great Carthusian monastery, near Milan, are ornamented in this manner. From these beginnings developed the Tarsia-work of Italy of a century later, which, dealing at first with geometrical patterns in wood, developed into inlaid representations of architecture, views, figures, and drapery, and finally into foliate scrolls of modern marquetry. Marquetry-work in furniture was greatly elaborated in France, Germany, and Holland towards the close of the 17th century, and workers in wood found great delight in skilful elaboration of intricate designs. Towards the close of the 17th century a new development of marquetry was effected by a French artist, Charles André Boule, in the exclusive use of inlaid veneers of tortoiseshell and brass, now known as Buhl-work. Both in design and execution Boule's work was of remarkable quality; the colour of his tortoiseshell was frequently heightened by a backing of gold or vermilion, and his brass-work was enriched with skilful engraving. Towards the close of the 18th century, while marquetry of a most elaborate character was being made in Germany and Italy, the richest triumphs of the art were produced in France by the famous ebenistes Reisner and Roentgen; but the Revolution put an end for the time to the manufacture.
Pietra-dura, which consists of an inlay of bright-coloured, hard, and precious stones, in slabs of marble or in panels of wood, is allied to the ancient mosaic-work which flourished in the palmy days of Rome; but true mosaic, although embedded, is not inlaid. Pietra-dura began to be made in Italy in the 15th century, but its extreme costliness prevented its extensive application. Two varieties were made in Italy, one being an inlay of minute pieces of stones with colours so arranged as to form a design or picture, like mosaics of larger size. This is known as Roman mosaic, in contradistinction to Florentine mosaic, which consists of slices of stone shaped and inserted to form definite portions of the required design. This latter class of inlaid-work was introduced into India by a French artist, Austin de Bordeaux, who decorated the famous Taj Mahal at Agra in pietra-dura of the richest and most elaborate character. The art then took root in that region, and to this day pietra-dura of manifestly European character in design continues to be a characteristic art industry of Agra.
The ornamental treatment of metals by inlaying is principally confined to the encrusting and inlaying of wire and fine plates of gold and silver into iron, steel, and bronze. The inlaying of gold and, to a minor degree, silver wire into iron or steel is known as Damascening (q.v.). In India such damascening is known as Kuft-work, and extensively practised in the North-western Provinces. Effective combinations of inferior metals are also made in India; silver inlaid in a black alloy of copper, lead, and tin being known as Bidri-work, from Bidar, in the Deccan. Combinations of copper and brass, and of brass and tin, are also common in the household vessels of the Hindus. The Japanese, who possess many alloys, excel in combining and inlaying them, often in relief, in their art metal manufactures.