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Smithsonian National Museum of Natural History

Blue Heart Diamond

Photograph of the Blue Heart diamond (NMNH G4873), digitally enhanced by SquareMoose for a 2017 jewelry publication by the Hillwood Museum
Photo by Chip Clark and digitally enhanced by SquareMoose. Click to zoom.
Catalog Number NMNH G4873-00
Locality South Africa
Weight 30.62 ct

Gift of Mrs. Marjorie M. Post in 1964.This object was designed by Harry Winston, Inc.

The remarkable Blue Heart Diamond was found at the Premier Mine, South Africa in 1908. This 30.62ct heart-shaped, brilliant cut blue diamond was faceted by French jeweler Atanik Eknayan of Paris in 1910 from a 100.5 carat piece of rough, purchased in 1909 from the Premier Transvaal Diamond Mining Company. The stone was then purchased by the French jeweler, Pierre Cartier in 1910 and set as the centerpiece of a lily-of-the-valley ornament necklace and sold to the Unzue family of Argentina that same year. In 1936, Maria Unzue gave the necklace to her niece, Angela Gonzalez Alzaga, as a wedding present. It was next acquired by Van Cleef & Arpels in 1953 and was reset into a pendant that also featured a 2.05 carat pink diamond and another blue diamond weighing 3.81 carats from the original Cartier necklace. Later that year the diamond was sold to Swiss industrialist Baron Hans Heinrich Thyssen-Bornemisza. In 1959, the Blue Heart Diamond was again sold, this time to Harry Winston, Inc., by the Baron’s ex-wife Nina Dyer. Winston mounted it in its present platinum ring setting, surrounded by 25 round brilliant cut colorless diamonds with a total weight of 1.63 carats. Mrs. Marjorie Merriweather Post, the last private owner of the diamond, purchased the ring from Winston and generously gifted the Blue Heart Diamond to the National Gem Collection in 1964. The Blue Heart Diamond is approximately two-thirds the size of the Hope Diamond, but its heart-shaped brilliant cut and lively blue color have made it one of the collection’s most popular gems. In 1997, the Gemological Institute of America (GIA) graded the Blue Heart as a natural fancy deep blue diamond with a clarity grade of VS-2 (very slightly included). The blue color is due to trace amounts of boron replacing some of the carbon atoms in the diamond’s crystal structure.



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