Lot 1689. 4.13 carats Type IIa Diamond Ring, Harry Winston. Estimate 1,600,000 — 2,000,000 HKD. Photo: Sotheby's.

Set with a brilliant-cut diamond weighing 4.13 carats, flanked by two tapered baguette diamonds, mounted in platinum, signed Winston and with maker's mark for Jacques Timey. Ring size: 6¾. 

Accompanied by GIA report numbered 5171540391, dated 25 March 2016, stating that the 4.13 carat diamond is D Colour, Internally Flawless; further accompanied by diamond type classification report stating that the diamond is determined to be a Type IIa diamond. Type IIa diamonds are the most chemically pure type of diamond and often have exceptional optical transparency.