Legendary blue diamonds not closely related after all

WASHINGTON — After decades of speculation, the truth can now be told: The famed Hope Diamond and its chief rival, the Wittelsbach-Graff Diamond, were not cut from the same stone, according to a group of scientists led by Jeffrey Post, curator of the National Gem Collection at the Smithsonian Institution.

"There is an uncanny resemblance, but they are different," said Post, announcing his team's findings at the Smithsonian's National Museum of Natural History. "They are not part of the same crystal or rough. Perhaps they are distant cousins, but not brothers and sisters."

The two diamonds were examined under a variety of microscopes and lights at the Smithsonian to try to settle some centuries-old mysteries. Could the two have originally been part of the same diamond? Are they twins? Why do they look so similar to the naked eye?

The opportunity to probe deeply into these questions came about because the Wittelsbach-Graff Diamond — which has not been on public display for more than 50 years — has been lent to the Smithsonian for a bit more than six months, displayed in the same hall as the Hope.

"This is the most famous diamond people have never seen," said Post. He provided a peek at the Wittelsbach-Graff last week. "Literally generations have gone by when no one has seen it," Post said of the diamond, last shown to the public in 1958.

"The tests supported the fact that they are extremely similar, in their color, 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 polarizers.

"The detailed pattern is different in the two," he said.

The Wittelsbach-Graff is 31.06 carats and, like the Hope, boasts a penetrating, though slightly less intense, blue color. It is two-thirds the size of the Hope, and two-thirds as blue. The diamond entered into jewelry lore in the 17th century, when Philip IV of Spain gave it to his daughter, the Infanta Margarita Teresa, upon her engagement to Emperor Leopold I of Austria. The diamond ended up with the House of Wittelsbach, a ruling Bavarian family, in 1722.

After World War I, Bavaria became a republic and in 1931 the crown jewels of the Wittelsbach family were sold at auction. Out of sight for a while, the diamond was displayed at the World Exhibition in Brussels, Belgium, in 1958. Laurence Graff, a London-based jeweler, bought the diamond in 2008 for $24.3 million and is lending it to the Smithsonian through Aug. 1.

The Hope is 45.52 carats and was given to the museum by Harry Winston in 1958. It had passed through many royal hands, beginning in 1668, when King Louis XIV purchased the stone. It was bought by the Cartier jewelry firm in 1909 and the jeweler sold it to Evalyn Walsh McLean, a prominent Washington, D.C. hostess, in 1911. The Winston company bought her estate jewels after her death in 1947 and donated the diamond to the Smithsonian.

But whether the two originated from the same stone in India, or even the same mine, believed to be the Kollur mine in Golconda, had always been a question.

One way scientists attempted to answer the question 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 has a lot of these properties.

Last week, Post placed the Wittelsbach-Graff on a small pillow and held a UV ray light over the visiting diamond. In seconds, it glowed. And, Post said, "one of the big differences is that the Wittelsbach-Graff had a longer phosphorescence."