Feature Articles

These are two of the great jewels that helped conjure up the celebrity of the diamond. Steeped in legend and both displaying a rare, dark blue hue, they have beguiled and fascinated gem aficionados for centuries. Each has its own history, but are they related?

 
First there is the Hope Diamond. Rumoured to be cursed, it first achieved fame more than 350 years ago, when it was bought in India as a crudely cut triangular shaped stone weighing 112 carats by the French adventurer of Flemish origin Jean-Baptiste Tavernier. He sold it to France’s King Louis XIV, who had the blue diamond cut into a heart-shape weighing 68.8 carats. It was set in gold and suspended on a neck ribbon for the King to wear on ceremonial occasions. In September 1792, while Louis XVI and his family were confined in the Palais des Tuileries, thieves stole most of the Crown Jewels.
 
In 1839, the diamond reappeared in a published catalogue of the gem collection of Henry Philip Hope, who provided it with its name. After changing hands many times, it was bought in 1949 by the New York diamond dealer Harry Winston. Winston donated it to the Smithsonian Institution in Washington, D.C., in 1958, famously sending it to the museum by mail in a plain brown paper bag. It can now be viewed in the Smithsonian’s Natural History Museum as part of the celebrated coloured diamond collection.
 
Then there is the Wittelsbach Diamond. Weighing 35.56 carats, it also is believed to be of Indian origin. The diamond formed part of the gift given in 1664 by King Philip IV of Spain to his 15-year-old daughter, the Infanta Margareta Teresa, on the occasion of her wedding to Emperor Leopold I of Austria. It remained as part of the Austrian crown jewels until 1717, when Archduchess Maria Amelia, the daughter of the Emperor Joseph I, married Bavarian Crown Prince Charles Albert. The jewel thus became the “family diamond” of the House of Bavaria, the Wittelsbachs, from whence its name.
 
The last King of Bavaria to wear the Wittelsbach was Louis III who reigned until 1918 when Germany became a republic. In 1931 during the depths of the Great Depression, part of the Bavarian crown jewels was sold at Christie's in London. Reportedly the Wittelsbach Diamond was not sold, but neither did it return to its former place of display in Munich.
 
It was rumoured that the Wittelsbach had been sold illegally in 1932, and it is now known that the diamond was sold in Antwerp in 1951 and then again in 1955. Three years later, visitors at the World Exhibition in Brussels flocked to an exhibition of jewellery which included a large blue diamond. It later turned out that this was the Wittelsbach Diamond. The diamond today is officially called the Wittelsbach-Graff, after the London jeweller Laurence Graff who bought it in 2008 at a Christie’s for $23.4 million.
 
Diamantaires have speculated for many years whether the Hope and the Wittelsbach were cut from the same stone. But an extensive investigation by a group of scientists led by Jeffrey Post, curator of the National Gem Collection at the Smithsonian Institution, has concluded that the two blue diamonds are unrelated.  The chance to test them came about after Graff decided to lend the Smithsonian the gem for six months.
 
"There is an uncanny resemblance, but they are different. They are not part of the same crystal or rough. Perhaps they are distant cousins, but not brothers and sisters," Post said in comments to the media.
 
"The tests supported the fact that they are extremely similar, in their colour, in the way they phosphoresce. It's amazingly similar," Post said. At the same time, the differences became quickly apparent under a diamond view microscope that showed dislocations, and a light microscope that showed the cross polarisers.”
 
"The detailed pattern is different in the two. The cross polarizer reveals evidence of strain. Under the light you see the pattern and it was very different in the Hope than the Wittelsbach. We can't match them up as the same diamond. It is likely that they had a very similar geologic history, but did not come from the same original stone," Post said.
 
There have long been questions as to whether the two diamonds came from the same stone in India, or even the same mine, believed to be the Kollur mine in Golconda.  To investigate this theory, careful mineralogical, gemmological and spectroscopic analyses of both diamonds were carried out at the Smithsonian in January.
 
Both diamonds displayed similar clarity and deep blue colour. Mid-IR spectroscopy confirmed that both were type IIb. In addition, both displayed long-lasting strong orange-red phosphorescence, as well as nearly identical phosphorescence spectral features. The intensity ratio of the two bands was nearly the same for the two stones, although the half-life of the 660 nm band in the Wittelsbach-Graff diamond was slightly longer than for the Hope.
 
Despite their close similarities, some clear differences were seen. In the DiamondView deep-UV luminescence imaging system, both diamonds showed well-developed dislocation networks with moderate-to-strong blue fluorescence throughout the entire stone, but the scale of the network patterns differed significantly. Post said that preliminary conclusions indicated that they were unlikely to have come from the same crystal.
 
Another way scientists attempted to answer the issue of common origins was by looking at the stones with a shortwave ultraviolet light to see the amount of orange to fiery red phosphorescence they emitted. The Hope, which has been examined many times over the years, has many of these properties. When Post placed the Wittelsbach-Graff on a small pillow and held a UV ray light over the visiting diamond, it glowed in seconds. Post said: "The Wittelsbach-Graff had a longer phosphorescence."
 
Both scientists and the general public have been anticipating the rare pairing of these two famous stones, because Wittelsbach-Graff has not been on public display for more than half a century. "This is the most famous diamond people have never seen," said Post. "Literally, generations have gone by when no one has seen it," Post said of the diamond, which was last shown to the public in 1958.
 
With the addition of the Wittelsbach-Graff, the Smithsonian will have, if only temporarily, three of the world's best-known blue diamonds. The third is the Blue Heart Diamond, a 30.82-carat stone that was mined in 1908, once owned by Marjorie Merriweather Post and given to the Smithsonian in 1964.
 
All photos by Chip Clark.