A Ceylon cushion and oval-cut sapphire and diamond necklace. Estimate $375,000 – $475,000. Photo Christie's Image Ltd 2015

Designed as a graduated series of nine cushion and oval-cut sapphires, weighing from approximately 26.86 to 4.71 carats, each within a two-row circular-cut diamond surround, to the circular-cut diamond backchain, mounted in platinum, 17 ins.

With report CS 66153 dated 13 February 2015 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of these sapphires would be classified as Ceylon (Sri Lanka). No gemological evidence of heat

Christie's. MAGNIFICENT JEWELS, 14 April 2015, New York, Rockefeller Plaza