Some reports refer to this unusual diamond as the "Eugenie Blue", although it is now recognized that there is no evidence that the Empress ever owned the Blue Heart diamond.
The Blue Heart weighs 30.82 carats and has a rare, deep blue color. The Parisian firm Atanik Ekyanan of Neuilly cut it into a heart shape in 1909 or 1910, and this date raises the issue of whether the rough stone came from Africa or from India. In 1910 Cartier purchased the diamond and sold it to an Argentinean woman named Mrs. Unzue. At the time, it was set in a lily-of-the-valley corsage and remained so until Van Cleef & Arpels bought the gem in 1953. They exhibited it set in a pendant to a necklace valued at $300,000 and sold it to a European titled family. In 1959 Harry Winston acquired the gem, selling it five years later, mounted in a ring, to Marjorie Merriweather Post. Mrs. Post donated the Blue Heart to the Smithsonian Institute in Washington D.C., where it remains to this day.