A diamond ring. Photo Christie's Image Ltd 2012

Set with a pear-shaped diamond, weighing approximately 6.10 carats, flanked on either side by a pear-shaped diamond, mounted in platinum. Estimate $400,000 - $600,000

With report 2125998152 dated 17 July 2012 from the Gemological Institute of America stating that the diamond is D color, internally flawless clarity, with excellent polish and excellent symmetry

Accompanied by a supplemental letter stating that the diamond has been determined to be a Type IIa diamond. Type IIa diamonds are the most chemically pure type of diamond and often have exceptional optical transparency. Type IIa diamonds were first identified as originating from India (particularly from the Golconda region) but have since been recovered in all major diamond-producing regions of the world. Among famous gem diamonds, the 530.20 carat Cullinan I and the 105.60 carat Koh-i-noor, are examples of Type IIa 

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