An examination of the Hennell archive reveals extensive sketches and leger notes, detailing stone breakdowns, manufacturing costs, clients names and price codes, with the entry for the present lot dating the design to December 1929; its bold geometric form, contrasting colours and use of carved rock crystal is typical of what was later to become known as Art Deco. The firm was established in 1736, quickly becoming one of London's foremost silversmiths, and towards the late 18th century begun producing jewellery. It was under the creative vision of designer Charles Bruno in the 1920s-30s that the company really reached its zenith, the style and quality rivalling international houses such as Van Cleef & Arpels, Cartier and Boucheron and a client list reading like a who's who of high society, including the Russian Royal Family, British Nobility and the Astors, Vanderbilts and Rockefellers.