The Blue Heart Diamond, also known as the Cœur Bleu, is a remarkable gem that captures the imagination with its deep blue color and perfect heart-shaped cut. This diamond, weighing precisely 30.62 carats, is ranked among the world’s most unique and fascinating gemstones.
A South African diamond
Although the exact details of its extraction are shrouded in mystery, it is assumed that the Blue Heart was discovered around 1900 in South Africa, famous for its diamonds of exceptional quality. The Premier Transvaal Diamond Mining Company purchased the nearly 100-carat rough diamond in 1909 and had it cut by Atanik Eknayan in Paris, who reduced the stone’s weight to its current 30.62 carats.
A long journey and many transformations
In 1910, Pierre Cartier acquired the Blue Heart diamond. That same year, Cartier sold it as a necklace to Maria Unzue, an Argentine aristocrat. The jewel thus entered the Unzue family collection, where it remained for 43 years.
In 1953, Van Cleef & Arpels acquired the diamond and decided to add it to a sumptuous necklace, together with a 2.05-carat pink diamond and a 3.81-carat blue diamond from Cartier’s original necklace. A few years later, Van Cleef & Arpels sold this exceptional jewel to Baron Hans Heinrich Thyssen-Bornemisza, a renowned Swiss industrialist. However, the diamond remained in his possession for only six years.
In 1959, the Blue Heart changed hands again, passing to Harry Winston, who acquired it from Nina Dyer, the Baron’s ex-wife and a great lover of jewelry, as evidenced by this incredible brooch. The New York jeweler decided to mount the diamond on a platinum ring.
The same year, the ring was purchased by Marjorie Merriweather Post, an influential American socialite and philanthropist. Mrs. Post was known for her passion for exceptional jewelry (see related article). In 1964, it was donated to the Smithsonian National Museum of Natural History in Washington, D.C. by Marjorie Merriweather Post, where it is now exhibited among the world’s most famous diamonds, such as the Hope. In 1997, the diamond was appraised by the GIA as “fancy deep blue” with a purity grade of VS2 (very slightly included).
