Lot 257. A 15.50 carats Burmese Sapphire and Diamond Ring, Harry Winston. Estimate 100,000 — 150,000 USD. Lot sold 275,000 USD. Photo: Sotheby's.

Set with a cushion-cut sapphire weighing 15.50 carats, accented by clusters of pear-shaped diamonds, size 7¾, signed Winston.

Accompanied by AGL report no. 1085824 stating that the sapphire is of Burmese origin, with no indications of heating. 

Sotheby's. Magnificent Jewels New York, 05 Dec 2017