400-year-old diamond may fetch $4 million at auction

Next month, Sotheby's will auction a 400-year-old diamond that is estimated to be worth between $2 million and $4 million. The "Beau Sancy" is one of the world's oldest known diamonds and weighs 34.98 carats.
The diamond will be on public display in Paris, London and Zurich until it goes up for auction in Geneva on May 14. View more photos of the Beau Sancy.
The Beau Sancy once belonged to France's Queen Marie de Medici and was originally cut from a gem mine in the Indian city of Golconda. It was owned by the last Emperor of Germany, Wilhelm II, before being acquired by a private European owner.
[Related: World's first all-diamond ring; worth $70 million]
Diamond website overabillion.com says the Beau Sancy gets its name from 16th century French financier and diplomat Nicholas Harlay de Sancy. The gem is described as a "perfect, colorless, rounded pear-shaped diamond."