René Boivin. A Rock Crystal, Diamond and Platinum Brooch. Photo Philips de Pury & Company

Centering on a rectangular rock crystal frame, to the bombé gold terminals, accented with old-cut diamonds, mounted in 18K white gold, length 2 3/4 inches.  With French assay marks andhallmarks for René Boivin, with a letter of authenticity. ESTIMATE $20,000-30,000 

Philips de Pury & Company. 19 April 2012 4pm. 450 Park Avenue, New York. Enquiries Nazgol Jahan njahan@phillipsdepury.com - + 1 212 940 1283