Jewels once belonging to ill-fated French Queen Marie-Antoinette are being auctioned in what is being called one of the most important royal jewellery auctions in history, reports BBC News.
They have not been seen in public for 200 years and include a pearl and diamond pendant, earrings and necklace.
The jewels are part of a major collection of jewellery being sold by Italy's royal Bourbon-Parma house.
The auction will take place in the Swiss city of Geneva on Thursday.
Sotheby's, which is auctioning the jewels, called it "one of the most important royal jewellery collections ever to appear on the market".
Deputy Chair Daniela Mascetti said: "This extraordinary group of jewels offers a captivating insight into the lives of its owners going back hundreds of years."
But she noted the "inherent beauty of the pieces themselves; the precious gems they are adorned with and the exceptional craftsmanship they display are stunning in their own right".
One of the most prized items is Marie-Antoinette's Pearl, a natural pearl and diamond pendant, valued at up to 2 million dollars (£1.5m).
The natural pearl and diamond necklace and a pair of pearl and diamond earrings are both expected to fetch as much as $300,000, while a monogram ring with a lock of her hair is valued at up to $10,000.
Other items up for auction include pieces from King Charles X, the Archdukes of Austria and the Dukes of Parma, including a diamond tiara valued at up to $550,000.