A spessartite garnet and diamond ring, by Bulgari. Photo Christie's Image Ltd 2014

Set with a cabochon Mandarin garnet, stated to weigh approximately 29.65 carats, to the pear-shaped diamond shoulders, mounted in gold, ring size 6½. Signed Bulgari. Estimate CHF11,000 – CHF14,000 ($12,546 - $15,968)

Accompanied by report no. 73708 dated 27 March 2014 from the SSEF Swiss Gemmological Institute stating that the garnet is of Nigerian origin, with no indications of treatment

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