Platinum, sapphire and diamond necklace, France. Photo Sotheby's. 

The swag necklace of garland design, set with 18 cushion and oval-shaped sapphires weighing approximately 100.00 carats, accented by old mine, old European, single and rose-cut diamonds weighing approximately 10.75 carats, length 15¼ inches, with French marks, nine diamonds missing; circa 1910. Estimation 40,000 — 60,000 USD

James J. Hill, known as "The Empire Builder," founded Great Northern Railroad in 1866. This necklace belonged to his daughter Charlotte, who married George T. Slade, an executive of Great Northern Railroad and Yale classmate of her brother, Louis W. Hill. In 1906 their wedding was one of the grandest ever seen by St. Paul society. 

Sotheby's. Magnificent Jewels.New York | 11 déc. 2013 - www.sothebys.com