Lot 205. Platinum, Colombian Emerald and Diamond Brooch, Marianne Ostier. Estimate 175,000 — 275,000 USD. Photo Sotheby's.

The round hollow-back mixed-cut emerald measuring approximately 21.3 to 20.9 mm by 9.6 mm, framed by pear and marquise-shaped diamonds weighing approximately 19.50 carats, with maker's mark. With signed box.

Accompanied by AGL report no. CS 1073946 stating that the emerald is of Colombian origin, clarity enhancement: minor, type: traditional.