Sotheby's had expected the cushion-shaped stone to fetch between 850,000 and 1.7 million francs, or $1 million to $2 million. Bidders blew past that range. The auction house did not name the buyer, a private collector.

The 197.80-carat Ceylon sapphire likely came from the Mughal Empire in south Asia and made its way into Russia's imperial jewels in the 19th century. Sotheby's calls it one of the most important surviving gemstones from the Russian court.

Dowager Empress Maria Feodorovna, Czar Nicholas II's mother, wore the sapphire at the Winter Palace Ball of 1903. The auction house described that night as "widely regarded as the last great spectacle of Imperial Russia and immortalized in some of the most iconic images of the Romanov court." After the Russian Revolution, the sapphire appeared in inventory records before it entered the Soviet government's dispersal sales of imperial treasures.

The winning bidder gets a stone with a paper trail running from the Mughal Empire to the Romanov court to a Soviet sale.