Platinum, 18ct gold and diamond 'Signature X' ring, Jean Schlumberger, Tiffany & Co., designed as a continuous series of pairs of round brilliant-cut diamonds alternating between X-shaped motifs, the diamonds together weighing approximately 1.18 carats, size M, signed Tiffany & Co., Schlumberger. Literature: John Loring, Tiffany Diamonds, Harry N. Abrams, New York, 2005, p. 230 (illustrated, another example)