Lot 173. 14.49 carats Colombian emerald and diamond ring, Harry Winston. Estimate 305,000 — 505,000 CHF. Photo: Sotheby's

Set with a step-cut emerald weighing 14.49 carats, within a frame of pear-shaped diamonds, size 53, signed Winston, maker's mark for Jacques Timey..

Accompanied by SSEF report no. 86892, stating that the emerald is of Colombian origin, with a minor amount of oil in fissures. 

Sotheby's. Magnificent Jewels and Noble Jewels, Sessions 1 and 2, Genève, 16 mai 2017, 10:30 AM