An important 16.98 carats Colombian emerald and diamond 'Trombino' ring, by Bulgari. Estimate CHF330,000 – CHF480,000  ($338,620 - $492,539). Photo Christie's Image Ltd 2015.

Set with an oval cabochon emerald, weighing approximately 16.98 carats, to the baguette and circular-cut diamond surround and shoulders, ring size 7¼, mounted in platinum, in Bulgari leather case
Signed Bvlgari 

Accompanied by report no. CS64065 dated 9 April 2015 from the AGL American Gemological Laboratories stating that the origin of the emerald is Colombia, with minor clarity enhancement, and a 'Jewel Folio'. 
Report no. 15038237 dated 25 March 2015 from the Gübelin GemLab stating that the origin of the emerald is Colombia, with indications of minor clarity enhancement. 

CHRISTIE'S. GENEVA MAGNIFICENT JEWELS, 10 November 2015, Geneva