In 1933, records show the Archduke deposited the stone in the vault of the Hungarian General Credit Bank.
"Three years later it was sold to a European banker, and kept in France, locked away in a safe deposit box, where fortunately it remained undiscovered during World War Two," the auction house said.
Decades later it surfaced at auction in 1961 and again at Christie's in November 1993, netting 9.7 million Swiss francs, equivalent to $6.5 million at the time, the auction house said.
The stone was subsequently "slightly recut".
Christie's is privately held by French billionaire Francois Pinault.