A Diamond Ring. Photo Christie's Image Ltd 2013

Set with a rectangular-cut diamond, weighing approximately 52.58 carats, flanked on either side by tapered baguette-cut diamonds, mounted in platinum. Estimate $9.5 to $12.5 million

With report 1132889310 dated 3 October 2013 from the Gemological Institute of America stating that the diamond is D color, Internally Flawless clarity 

With report 13090169 dated 22 October 2013 from the Gübelin Gem Lab stating that the diamond is D color, Internally Flawless clarity 

Accompanied by a supplemental Appendix from the Gübelin Gem Lab stating that the diamond has been determined to be a Type IIa diamond and displays the outstanding colour and appearance for which the term “Golconda” is so famous.

Christie's. MAGNIFICENT JEWELS. 10 December 2013. New York, Rockefeller Plaza -www.christies.com