Platinum, Sapphire And Diamond Brooch, Georges Thibault, France, Circa 1925.  Photo Sotheby's

The bar brooch set in the center with a square emerald-cut diamond weighing approximately 1.25 carats, framed by buff-topped sapphires, bordered by round and old European-cut diamonds weighing approximately 3.20 carats, partial maker's mark, French assay marks. Estimate  12,000-15,000 USD

Sotheby's. Magnificent Jewels, New York 20 september 2011 www.sothebys.com