Sotheby's organised the auction, featuring jewels unseen in public for two centuries, in Geneva.
The company also said the pendant set a new record price for a pearl jewel sold at auction.
The 10 items, belonging to the Italian royal House of Bourbon-Parma, had been estimated to fetch a total of roughly three million dollars (2.7 million euros) sold for a combined sum of nearly 43 million dollars (38 million euros).
Marie-Antoinette and King Louis XVI were executed in 1793 and their 10-year-old son died in captivity.
Only their daughter, Marie Thérèse of France, survived.
She passed on the treasures to her niece and adopted daughter, Louise of France, Duchess of Parma, who in turn left them to her son, Robert I, the last ruling Duke of Parma.