An oval-cut sapphire and diamond ring. Photo Christie's Image Ltd 2014

Set with a cushion-cut purple sapphire, weighing approximately 10.16 carats, flanked on either side by a tapered baguette-cut diamond, mounted in platinum. Estimate $60,000 – $80,000

With report CS 59786 dated 10 March 2014 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of this material would be classified as Madagascar. No gemological evidence of heat

Christie's. MAGNIFICENT JEWELS, 16 April 2014, New York, Rockefeller Plaza - www.christies.com