Lot 269. An important 16.13 carats, D color, VVS1 clarity Type IIa  diamond ring, by Graff. Estimate USD 1,300,000 - USD 1,800,000. Price Realised USD 1,537,500 © Christie's Images Ltd 2016.

Set with a cut-cornered rectangular step-cut diamond, weighing approximately 16.13 carats, flanked on either side by a tapered baguette-cut diamond, ring size 5 1/4, mounted in platinum, in a Graff navy leather case. Signed Graff

Accompanied by report no. 15242735 dated 25 October 2016 from the GIA Gemological Institute of America stating that the diamond is D color, VVS1 clarity, with excellent polish and symmetry; accompanied by a working diagram indicating that the clarity of the diamond is potentially Internally Flawless 

With a supplemental letter from the Gemological Institute of America 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, 7 December 2016, New York, Rockefeller Plaza