A sapphire and diamond ring, by Mouawad. Photo Christie's Image Ltd 2013

Set with a cut-cornered rectangular-cut sapphire, weighing approximately 20.70 carats, to the shield-shaped diamond shoulders, weighing approximately 1.01 and 0.83 carat, mounted in gold, ring size 6. Signed Mouawad. Estimate:  $522,402 – $733-586

Accompanied by report no. 63477 dated 29 May 2012 from the SSEF Swiss Gemmological Institute stating that the sapphire is of Burmese origin, with no indications of heating, and an Appendix indicating that the sapphire’s ‘vivid blue colour is due to a combination of well-balanced trace elements in the gemstones, typical and characteristic for the finest sapphires of Mogok, Burma.’

Report no.1116022 dated 3 December 2011 from the Gübelin GemLab stating that the sapphire is of Burmese origin, with no indications of heating

Report no. 1147816695 dated 20 March 2013 from the GIA Gemological Institute of America stating that the 1.01 carat diamond is E colour, VS1 clarity

Diamond dossier no. 6142818448 dated 20 March 2013 from the GIA Gemological Institute of America stating that the 0.83 carat diamond is D colour, VVS2 clarity

Christie's. MAGNIFICENT JEWELS. 12 November 2013. Geneva - www.christie's.com