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

Of bombé design, set with a cushion-cut sapphire, weighing approximately 14.54 carats, within an old European and old mine-cut diamond surround, mounted in platinum. Estimate $725,000 - $925,000. Price Realized $875,000

With report CS 42693 dated 30 July 2010 from the American Gemological Laboratories stating that it is the opinion of the Laboratory that the origin of this sapphire would be classified as Kashmir. Heat enhancement: None

With report 12055254 dated 11 May 2012 from the Gübelin Gem Lab stating that gemmological testing revealed characteristics consistent with those of sapphires originating from Kashmir. No indications of heating

With report 5151389025 dated 15 April 2013 from the Gemological Institute of America stating that the origin of this sapphire is Kashmir. No indications of heating

Christie's. MAGNIFICENT JEWELS. New York, Rockefeller Plaza. 10 December 2013 - www.christies.com