Lot 325. Important 16.92 carats type IIa diamond ring, Harry Winston. Estimate 1,110,000 — 1,910,000 CHF. Photo: Sotheby's.

Set with a marquise-shaped diamond weighing 16.92 carats, between tapered baguette diamonds, size 49, signed Winston, maker's mark. 

Accompanied by GIA report no. 2183227935, stating that the diamond is D Colour, VVS1 Clarity, together with a working diagram stating that the diamond may be internally flawless after minor repolishing, also accompanied by a type IIa classification letter.