A diamond three-stone ring. Photo courtesy Bonhams.

centering a cut-cornered rectangular-cut diamond, weighing 12.02 carats, with rectangular-cut diamond shoulders, weighing 2.39 and 2.38 carats, and a plain mount; mounted in platinum; size 5 1/4. Sold for US$ 266,500 (€192,920)

Accompanied by GIA report #5141792418, dated June 22, 2012, stating the central diamond as: 12.02 carats, J color, VS1 clarity.

Accompanied by GIA report #2141813391, dated July 11, 2012, stating one of the sidestones as: 2.39 carats, K color, VS1 clarity.

Accompanied by GIA report #6147813415, dated July 11, 2012, stating one of the sidestones as: 2.38 carats, L color, VS2 clarity.

Bonhams. Fine Jewellery New York. 15 Oct 2012 - www.bonhams.com