An emerald and diamond ring, by Chatila. Photo Christie's Image Ltd 2014

Set with an octagonal step-cut emerald, weighing approximately 13.69 carats, flanked on either side with triangular-cut diamonds, mounted in gold, ring size 6¾, in green Chatila case. Signed Chatila. Estimate CHF140,000 – CHF220,000 ($160,636 - $252,427)

Accompanied by report no. 71773 dated 12 December 2013 from the SSEF Swiss Gemmological Institute stating that the emerald is of Colombian origin, with indications of moderate amount of artificial resin

Report no. 1005215 dated 31 May 2010 from the Gübelin GemLab stating that the emerald is of Colombia origin, with indications of minor clarity enhancement

Christie's. GENEVA MAGNIFICENT JEWELS. 14 May 2014, Geneva -http://www.christies.com/