Lot 430. Platinum and fancy blue diamond ring, Tiffany & Co., circa 1900. Estimate 300,000-500,000 USD. Lot sold 2,434,500 CHF. Photo Sotheby's

The modified marquise-shaped diamond of fancy blue color weighing 3.54 carats, within a delicate mounting set with old European-cut and single-cut diamonds weighing approximately .35 carat, size 3½, bearing partial signature 'T' for Tiffany & Co., two diamonds missing. With fitted box signed Tiffany & Co. 

Note: Accompanied by GIA report no. 5141498993 stating that the diamond is Fancy Blue, Natural Color, VS1 clarity.

Centered by a diamond of enchanting cut and color, this exquisite piece has remained in the family since being presented to the current owner's great-great grandmother. The elegant mounting, with its millegrained borders and endearingly sweet floral motifs, prefigures the refinement and delicacy of the Edwardian era. Turn-of-the-century rings, particularly those by esteemed houses such as Tiffany & Co., appear with diminishing frequency in today's marketplace. For such a piece to be set with a Fancy Blue diamond is rarer still, making this ring a truly exceptional jewel.

Sotheby's. Magnificent Jewels. New York, 18 april 2012