An emerald and diamond pendant necklace by William Goldberg. Photo Christie's Image Ltd 2014

Suspending a modified cushion-cut emerald, weighing approximately 33.46 carats, enhanced by twelve Ashoka-cut diamonds, from a baguette and circular-cut diamond line, joined by three Ashoka-cut diamonds, weighing approximately 2.04, 2.01 and 1.56 carats, to the circular and baguette-cut diamond neckchain, 15½ ins., mounted in platinum. Signed William Goldberg, no. N1270. Estimate $300,000 – $500,000

With report CS 59903 dated 13 March 2014 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of this emerald would be classified as Colombia. Minor clarity enhancement, traditional type

With report 1006123 dated 17 June 2010 from the Gübelin Gem Lab stating that gemmological testing revealed characteristics consistent with those of emeralds originating from Colombia. Indications of minor clarity enhancement

With report 17251178 dated 18 June 2008 from the Gemological Institute of America stating that the diamond, weighing approximately 2.04 carats, is J color, VVS2 clarity

With report 15082626 dated 11 July 2006 from the Gemological Institute of America stating that the diamond, weighing approximately 2.01 carats, is H color, SI1 clarity

With report 5121037517 dated 6 May 2010 from the Gemological Institute of America stating that the diamond, weighing approximately 1.56 carats is I color, Internally Flawless clarity

Christie's. IMPORTANT JEWELS, 10 June 2014, New York, Rockefeller Plaza - http://www.christies.com/