This ring was recently sold in Geneva by Christie’s for CHF1,323,000 ($1,098,340)

From the lot note:

“Set with a rectangular-cut diamond weighing 28.82 carats, to the triangular-shaped diamond shoulders, mounted in platinum, ring size 6. Accompanied by report no. 17465770 dated 17 July 2008 from the GIA Gemological Institute of America stating that the diamond is I colour, VVS2 clarity ”

See details at Christie’s