Regent Diamond, Historical diamond in Galerie d'Apollon, France.

The Regent Diamond is a gemstone of about 140 carats on display in the Galerie d'Apollon at the Louvre and displays a cushion-cut shape with exceptional clarity. The stone is exhibited alongside other pieces from the French Crown Jewels collection and can be viewed by visitors in that setting.

The rough stone was found at Golconda in 1698 and weighed 426 carats. Thomas Pitt, governor of Fort St. George, bought it from the merchant Jamchand and sent it to London in 1702 hidden in his son Robert's shoe; Harris cut it to about 140 carats between 1704 and 1706. Philippe II, Duke of Orléans, bought it for the French Crown in 1717, and it entered the French royal treasury.

The name comes from Philippe II, Duke of Orléans, regent of France from 1715 to 1723, who bought the stone for the Crown in 1717. Earlier it was called Jamchand, after the Indian merchant who sold it to Thomas Pitt. Visitors see it in the Galerie d'Apollon, where it carries inventory number MV 1017.

The stone sits in the Galerie d'Apollon, the Louvre gallery rebuilt after a fire in 1661 for Louis XIV, next to the crown jewels and the collection's other gems. The gallery is reached from the Denon wing; the room is long and narrow, so the case is passed in one direction with the crowd. Look for inventory number MV 1017 on its label.

The stone was hidden during World War II in the plaster sealing the marble of a fireplace at the Château de Chambord. It escaped the 1887 auction of the crown diamonds, which jewellers Boucheron, Bapst and Tiffany & Co. attended, and is catalogued as MV 1017.