A fire opal and diamond cluster ring. Photo: Bonhams.

The raised oval mixed-cut fire opal, weighing 5.64 carats, within a brilliant-cut diamond surround, ring size M½. Estimate £2,500 - 3,500 (€3,000 - 4,300)

Accompanied by a report from The Gem & Pearl Laboratory stating that the fire opal is natural. Report number 09141, dated 18th December 2013.

Bonhams. JEWELLERY. 12 Feb 2014, London, Knightsbridge - www.bonhams.com