18 karat white gold, amethyst, emerald and diamond violet necklace, Michele della Valle. Photo Sotheby's

Designed as a graduated line of violets, the petals set with round amethysts weighing 23.95 carats, set in the center with small round diamonds, spaced by round emeralds framed by round diamonds, the clasp suspending two vines set with round diamonds completed by leaves set with round emeralds, the total diamond weight 4.34 carats, the total emerald weight 5.68 carats, length 15½ inches, signed Michele della Valle, numbered 120711. Lot 383. Estimation 40,000-60,000 USD

Sotheby's. Magnificent Jewels. New York | 18 avr. 2012, 10:00 AM www.sothebys.com