Piqué work was a method of inlaying gold, silver and sometimes mother of pearl into tortoiseshell and other materials to create truly stunning effects. Piqué originated in Italy in the mid 1600s and then spread to France where it was further developed as a technique. The English also enthusiastically adopted the method and English piqué jewelry is the most prevalent. Jewelry was first made with this technique in the early 1800s and piqué jewelry peaked in popularity in the 1850s to 1880s. It was considered appropriate for mourning because of the dark colors. It quite abruptly ceased to be made almost entirely by 1885. Earlier designs were much more naturalistic and softer; later designs became more geometric as production methods became more mechanized.
Generally, pure gold and silver were used as the metals. It is quite difficult to metal test such small amounts of metal but it can generally be assumed that if you have a piece of genuine tortoiseshell and the design is well executed that the gold or silver is high carat. Sometimes brass was also used. In order to embed the metals, the tortoiseshell was heated up first which caused it to expand and soften whilst the metals were worked in.
There were two types of piqué work: piqué point, in which gold or silver pins are driven into the tortoiseshell or other material to create the design and piqué posé, in which the design is engraved and then threads or small pieces of gold and silver are used to fill it in. You will sometimes hear piqué referred to as piqué d’or but this is only correct when referring to gold piqué work. Two major piqué artisans were: Laurentini and Charles Boulle.