The Blue Heart diamond is 30.82 carats. The gem was cut into its distinctive shape in 1909-1910 and was bought by Cartier shortly thereafter. Since then it has bounced around from a wealthy Argentinian woman, Van Cleef and Arpels, a European family, Harry Winston, Marjorie Merriweather Post, and, finally, the Smithsonian, where The Blue Heart has resided since 1964.