A sapphire and diamond dress ring by Jean Schlumberger, the central cut cornered step cut sapphire weighing 30.95 carats, claw set within a pave set brilliant cut diamond mount with beaded accents, above pave set brilliant cut diamond shoulders, approximately 3.00 carats total, signed Schlumberger on a plaque under the gallery, the shank stamped with the maker's mark of the atelier Henri Picq, finger size K 1/2 Born in 1907, Jean Schlumberger has become recognised as one of the master jewellery designers of the 20th century. He began designing costume jewellery for Elsa Schiaparelli in Paris in the late 1930's, and gathered around him such leading socialites and style icons as the Duchess of Kent, Daisy Fellowes and Diana Vreeland, from whom he received his first jewellery design commissions. After the end of the Second World War, Schlumberger opened a workshop in New York, followed by a boutique in Paris in 1950. In 1956 he was invited to become the Vice President of jewellery design at Tiffany & Co., making his name synonymous with Tiffany's jewellery design. The atelier of Henri Picq came to prominence in the early 20th century as the Parisian workshop that produced some of Cartier's finest jewels, including the 'Tutti Frutti' jewels of the 1920s.