A unique diamond necklace, Cartier, 1942. Photo Sotheby's

The front designed as a series of articulated stylised roses and floral motifs set with circular- and single-cut diamonds, each centring on a circular-cut stone, the back of geometrical links, similarly set, inner circumference approximately 425mm, signed Cartier, fitted case signed Cartier, New York. Estimate 550,000-725,000 CHF

Accompanied by Cartier certificate of authenticity no. GE2009-200.

NOTE: It is understood from Cartier that this extraordinarily beautiful and unique necklace was commissioned and designed in New York in 1942 using jewels which had been supplied by the client. Such remaking of jewellery was not uncommon in the first half of the 20th century as rapid changes in dress fashion, combined with the fact that jewels were being worn frequently and with great abundance, called for new jewel designs; this often necessitated the refreshing and re-designing of existing jewels.

The front of this necklace is remarkably similar in design to a stunning bracelet by Boucheron, created in 1925, sold by Sotheby's Geneva in May 2011, lot 485, and a bandeau by Boucheron of the same date.

Sotheby's. Magnificent Jewels, Geneva | 15 Nov 2011 www.sothebys.com