A diamond ring. Photo Christie's Image Ltd 2012

Set with a rectangular-cut diamond, weighing approximately 6.40 carats, the shoulders set with circular-cut diamonds, mounted in platinum. Estimate $500,000 - $700,000

With report 11368592 dated 1 March 2012 from the Gemological Institute of America stating that the diamond is D color, flawless clarity I

Christie's. Magnificent Jewels. 16 October 2012. New York, Rockefeller Plaza