A Colombian emerald and diamond ring, by Bulgari. Estimate CHF38,000 – CHF58,000 ($38,324 - $58,494). Photo Christie's Image Ltd 2015

The oval cabochon emerald set within a marquise and circular-cut diamond surround, ring size 3½, mounted in platinum, in red leather Bulgari case. Signed Bvlgari 

Accompanied by report no. 81298 dated 22 July 2015 from the SSEF Swiss Gemmological Institute stating that the origin of the emerald is Colombia, with indications of moderate amount of oil. 

Christie's. GENEVA MAGNIFICENT JEWELS, 10 November 2015, Geneva