Prince Georg Friedrich, 36, great-great-grandson of the last German Kaiser, inherited the nearly 35-carat diamond as part of the estate of the House of Prussia, after it was worn by some of Europe's most important queens over the previous four centuries.
On Tuesday it was sold at a Sotheby¹s auction in Geneva.
“It is set very simply in a hoop with a ring so it could be put on a necklace. It is a beautiful stone, but what is at least as exciting is the history it carries, with previous owners including the Medicis, Queen Mary and all the Kaisers of Prussia,” Philipp Herzog von Württemberg, chairman of Sotheby¹s Europe told The Local when the stone was first released for auction in February.
“This is one of the most important historical diamonds that has ever come to auction,” he said.
Experts had expected a selling price of about $2 million to $4 million for the 34.98 carat pear-shaped jewel. It sold for just below $9.7 million to an anonymous bidder who placed his bid via a telephone call.
Shortly after the auction began some 595 people called in, but it soon became clear that the bidding centred on at least five bidders, including both telephone bids and offers from those in the audience.
The House of Prussia owned the Beau Sancy and it had only been seen on public display four times in the last half-century. The great-great-grandson of the last German Kaiser inherited the diamond as part of the House of Prussia estate.
The jewel has been worn by royalty all over Europe over the last four centuries.