Tiffany & Co. An Art Nouveau Black Opal, Diamond and Enamel Necklace, 1900. Photo PHILLIPS

The front suspending an oval cabochon black opal, within an enamel and circular-cut diamond frame, to the collet-set peridot and white opal gold chain, mounted in 14K yellow gold, length 23 inches. Signed 'Tiffany & Co.'. Estimate $15,000 - 20,000. SOLD FOR $32,500.

PHILLIPS; JEWELS 6 DECEMBER 2012 NEW YORK