A colored diamond ring.  Photo Christie's Image Ltd 2012

Set with a modified cushion-cut fancy intense yellow diamond, weighing approximately 15.06 carats, to the circular-cut yellow diamond gallery and hoop, mounted in gold, ring size 6½. Estimate $320,000 - $500,000

With report 2145649768 dated 30 April 2012 from the Gemological Institute of America stating that the diamond is fancy intense yellow, natural color, VS1 clarity 

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