Platinum and diamond 'Quatre Plans' ring, René Boivin. Photo Sotheby's

Centering an old European-cut diamond weighing approximately .55 carat, accented by smaller old European-cut diamonds weighing approximately .50 carat, size 6, with French assay and maker's mark; circa 1934-1935.Estimate 7,500 — 10,000 USD 

Accompanied by a Certificate of Authenticity from Françoise Cailles.

Sotheby's. Magnificent Jewels, New York | 29 Apr 2014 - www.sothebys.com