An impressive 18.80 carats Type IIa diamond ring. Estimate $1,400,000 – $1,600,000. Photo Christie's Image Ltd 2015

Set with a marquise brilliant-cut diamond, weighing approximately 18.80 carats, flanked on either side by tapered baguette-cut diamonds, ring size 10, mounted in platinum

Accompanied by report no. 2165307339 dated 12 June 2015 from the GIA Gemological Institute of America stating that the diamond is D color, VVS1 clarity

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. IMPORTANT JEWELS, 20 October 2015, New York, Rockefeller Plaza