A coloured diamond ring. Photo Christie's Image Ltd 2014.

Centering upon a fancy dark orangy-brown oval-shaped diamond, weighing approximately 27.33 carats, to the pavé-set diamond and pink diamond double frame and triple shoulders, mounted in gold, ring size 6¼. Estimate CHF360,000 – CHF540,000 ($409,479 - $614,218)

Accompanied by report no. 5141721505 dated 23 May 2012 from the GIA Gemological Institute of America stating that the diamond is Fancy Dark Orangy-Brown colour

Please note that the pink diamonds have not been tested for natural colour

Christie's. GENEVA MAGNIFICENT JEWELS. 14 May 2014. Geneva - www.christies.com