A "mystery-set" sapphire and diamond flower brooch by Van Cleef & Arpels. Photo Christie's Image Ltd 2014

Designed as a calibré-cut sapphire flower, centering upon a circular-cut diamond cluster pistil, extending a baguette-cut diamond stem and circular-cut diamond leaves, mounted in platinum and gold. Signed Van Cleef & Arpels, N.Y. 61259. Estimate $90,000 – $120,000

Christie's. IMPORTANT JEWELS, 10 June 2014, New York, Rockefeller Plaza - http://www.christies.com/