A diamond ring, by Harry Winston. Photo Christie's Image Ltd 2013

Set with a marquise-shaped diamond, weighing approximately 15.59 carats, to the tapered baguette-cut diamond shoulders, ring size 2½ with ring sizer, in navy blue leather Harry Winston case and box. By Harry Winston. Estimate CHF950,000 – CHF1,450,000

Accompanied by report no. 1132672978 dated 21 July 2011 from the GIA Gemological Institute of America stating that the diamond is D colour, VVS1 clarity

Christie's. MAGNIFICENT JEWELS. 15 May 2013. Geneva