A sapphire and diamond ring. Photo Christie's Image Ltd 2014

Set with a cushion-cut sapphire, weighing approximately 7.55 carats, flanked on either side by an old mine-cut diamond, weighing approximately 1.06 and 1.05 carats, to the single-cut diamond shoulders, mounted in platinum. Estimate $30,000 – $50,000

With report 13075212 dated 24 July 2013 from the Gübelin Gem Lab stating that the gemmological testing revealed characteristics consistent with those of sapphires originating from Burma (Myanmar). No indications of heating

With report 69262 from the SSEF Swiss Gemmological Institute stating that the analysed properties confirm the authenticity of the sapphire. No indications of heating. Origin: Burma (Myanmar)

With reports 5141827395 and 215122240 dated 16 July 2012 and 22 January 2013 from the Gemological Institute of America stating that the old mine-cut diamonds, weighing approximately 1.06 and 1.05 carats, are F color, VS2 clarity

Christie's. MAGNIFICENT JEWELS, 16 April 2014, New York, Rockefeller Plaza - www.christies.com