At 55 carats, the Sancy diamond is cut in a pear shape. The Sancy diamond was first owned by Charles the Bold, Duke of Burgundy, who lost it in battle in 1477. The diamond is named after a later owner, Seigneur de Sancy, a French Ambassador to Turkey in the late 16th century.

He loaned it to the French king, Henry III who wore the diamond in the cap with which he concealed his baldness. Henry IV of France also borrowed the diamond from Sancy, but it was sold in 1664 to James I of England. In 1688, James II, last of the Stuart kings of England, fled with it to Paris. It disappeared during the French revolution.

Since 1906, this diamond has belonged to the Astor family of London.