Spinel and diamond necklace, Cartier. Photo Sotheby's

Composed of polished spinel beads, the front set with a floral motif pavé-set with brilliant-cut diamonds, the clasp similarly set, length of shortest row approximately 380mm, signed Cartier and numbered, French assay and maker’s marks, case stamped Cartier. Estimate:  29,000 – 49,000 CHF

Sotheby's. Magnificent Jewels and Noble Jewels. Genève | 14 mai 2013, www.sothebys.com