A diamond single-stone ring, by Hardy Brothersphoto Bonhams

The brilliant-cut diamond, weighing 5.07 carats, in a double four-claw setting to bifurcated similarly-cut diamond shoulders with diamond highlights of pink tint, tinted diamonds untested for natural colour, maker's pouch, ring size N. Estimate: £120,000 - 150,000, US$ 190,000 - 240,000

Hardy Brothers is one of Australia's most distinguished jewellers having been in business since 1853. They are also the only Australian jewellers to hold a Royal Warrant.

Accompanied by a certificate from GIA stating that the diamond, weighing 5.07 carats, is D colour, VS1 clarity. Certificate number 12262053, dated 29th October 2002.

Bonhams.Fine Jewellery, 25 Apr 2012. London, New Bond Street www.bonhams.com