An impressive 20.02 carats diamond ring. Estimate $650,000 – $850,000. Photo Christie's Image Ltd 2015

Set with a round brilliant-cut diamond, weighing approximately 20.02 carats, to the platinum hoop, ring size 6 1/2

Accompanied by report no. 2165589780 dated 4 September 2014 from the GIA Gemological Institute of America stating that the diamond is G color, SI1 clarity, with excellent cut and polish

An impressive 20.01 carats diamond ring. Estimate $550,000 – $650,000. Photo Christie's Image Ltd 2015

Set with a round brilliant-cut diamond, weighing approximately 20.01 carats, to the platinum hoop, ring size 6 1/2

Accompanied by report no. 2165589803 dated 18 November 2014 from the GIA Gemological Institute of America stating that the diamond is G color, SI2 clarity

Christie's. IMPORTANT JEWELS, 20 October 2015, New York, Rockefeller Plaza