Lot 209. Diamond ring weighing 16.82 carats, M. Gérard, 1970s. Estimate 480,000 — 770,000 CHF. © Sotheby's 2018

Set with a marquise-shaped diamond weighing 16.82 carats, size 52, signed M. Gérard, numbered, French assay mark for platinum and maker's mark, case stamped M. Gérard.

Accompanied by GIA report no. 5182916500, stating that the diamond is G Colour, VVS1 Clarity, together with a working diagram stating that the diamond may be internally flawless after minor repolishing, and a copy of Service Public du Contrôle des Diamants, Perles Fines, Pierres Précieuses report no. 011336, dated 6 December 1976.

Sotheby's. Magnificent Jewels and Noble Jewels, Geneva, 15 May 2018, 10:30 AM