An important diamond pendant necklace. Photo: Christie's Images Ltd 2014.

Suspending a pendant, set with a pear-shaped diamond, weighing approximately 24.53 carats, from a circular-cut and lozenge-shaped diamond link, to the fine link neckchain, mounted in platinum, 16 ins. Estimate $1,300,000 – $1,800,000

With report 2155575031 dated 5 August 2013 from the Gemological Institute of America stating that the diamond is D color, VS2 clarity 

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 and the 105.60 carat Koh-i-noor, are examples of Type IIa.

Christie's. MAGNIFICENT JEWELS, 16 April 2014, New York, Rockefeller Plaza -www.christies.com