A Superb Colombian Emerald and Diamond Ring. Photo Philips de Pury & Company

Set to the center with a rectangular-cut emerald, weighing approximately 16.84 carats, flanked on either side by half-moon shaped diamond shoulders, mounted in platinum and 18K yellow gold, size 6. ESTIMATE $85,000 - 100,000

With report no.11090021 dated 6 September 2011 from the Gubelin Gem Lab, stating that the emerald is of Colombian origin, with indication of minor clarity enhancement. 

Philips de Pury & Company. Jewels. 6 december 2012. http://www.phillipsdepury.com