A diamond single-stone ring. Photo Bonhams.

The pear-shaped diamond, weighing 2.77 carats, on a chevron-shaped single-cut diamond hoop, with a square-cut diamond highlight, mounted in platinum, maker's mark, UK hallmark, ring size H. Estimate £15,000 - 20,000 (€18,000 - 24,000)

Accompanied by a report from AnchorCert stating that the diamond weighing 2.77 carats is D colour, VVS2 clarity, Type IIa. Report number 20014873, dated 8 March 2014.

Bonhams. FINE JEWELLERY, London, New Bond Street, 30 Apr 2014 - www.bonhams.com