Superb 33.58 carats Type IIa cushion-shaped diamond ring. Estimate 4,870,000 — 6,800,000 CHF (4,594,346 - 6,415,104 EUR). Photo Sotheby's

Set with a cushion-shaped diamond weighing 33.58 carats, size 52.

Accompanied by GIA report no. 1162837348, stating that the diamond is D Colour, Flawless, Excellent Polish and Symmetry, together with a Type IIa classification letter. 

Sotheby's. Magnificent Jewels and Noble Jewels, Geneva, 12 May 2015, 10:30 AM