Inlay covers a range of techniques in sculpture and the decorative arts for inserting pieces of contrasting, often coloured materials into depressions in a base object to form ornament or pictures that normally are flush with the matrix. A great range of materials have been used both for the base or matrix and for the inlays inserted into it. Inlay is commonly used in the production of decorative furniture, where pieces of coloured wood, precious metals or even diamonds are inserted into the surface of the carcass using various matrices including clearcoats and varnishes. Lutherie inlays are frequently used as decoration and marking on musical instruments, particularly the smaller strings.
Perhaps the most famous example of furniture inlay is that of Andre-Charles Boulle (11 November 1642 - 28 February 1732) which is known as Boulle Work and evolved in part from inlay produced in Italy during the late 15th century at the Studiolo for Federico da Montefeltro in his Ducal Palace at Urbino, in which trompe-l'oeil shelving seems to carry books, papers, curios and mathematical instruments, in eye-deceiving perspective. The similar private study made for him at Gubbio is now in the Metropolitan Museum of Art.
In a wood matrix, inlays commonly use wood veneers, but other materials like shells, mother-of-pearl, horn or ivory may also be used. Pietre dure, or coloured stones inlaid in white or black marbles, and inlays of precious metals in a base metal matrix are other forms of inlay. Master craftsmen who make custom knives continue a tradition of ancient techniques of inlaying precious metals; additionally, many new techniques which use contemporary tools have also been developed and utilized as well by artisans.
Intarsia inlay in wood furniture differs from marquetry, a similar technique that largely replaced it in high-style European furniture during the 17th century, in that marquetry is an assembly of veneers applied over the entire surface of an object, whereas inlay consists of small pieces inserted on the bed of cut spaces in the base material, of which most remains visible.
The history of inlay is very old but it is still evolving alongside new technologies and new materials being discovered today. The technique of metal in metal inlay was sophisticated and accomplished in ancient China as shown in examples of vessels decorated with precious metals including this ding vessel (pictured) with gold and silver inlay from the Warring States period (403-221 BC).
The French cabinet maker Andre-Charles Boulle (1642-1732) specialised in furniture using inlays or metal and either wood or tortoiseshell together, the latter acting as the background. This type of inlay is known as "Boulle Work".
In 2016, a subsidiary company of Jean-Raymond Boulle discovered and has filed a patent for a new type of diamond inlay in keeping with Boulle Work, subsequently produced by AkzoNobel for application on cars, planes and yachts.
Pietra dura is the usual term in Europe for detailed inlays in contrasting colours of stones, including many semi-precious types; parchin kari is an Indian term. Pietra dura developed from the Roman Opus sectile, which was typically used on a larger scale, especially in floors. Cosmatesque work on walls and floors, and smaller objects, was a medieval intermediate stage, continuing ancient opus alexandrinum.
Inlaid artefacts have come down to us from the Ancient Mayan civilisation, among them, jade, mother of pearl and onyx inlaid into stone during the era that arts reached a peak during the seven centuries from 200 to 900 AD.
Pre-Dynastic Egyptian bone figure with eyes inlaid in lapis lazuli; inlaid eyes are found in sculpture from many periods
Egyptian bone plaque of a putto, with wax inlay, 4th century
Parchin kara (pietra dura) in stone on the Taj Mahal
Japanese netsuke in ivory with ink; the eyes are inlaid in shell. 19th century
Egyptian basin with silver inlay
(Walters Art Museum)
Japanese lacquerware Photograph Album Cover with ivory inlay, 1865