Green diamonds acquire their color from irradiation, a process that can take place naturally-deep inside the earth over millions of years-or artificially-in a laboratory in a matter of minutes. Because the spectra of an artificially irradiated green diamond are identical to the spectra of a naturally irradiated green diamond, it’s impossible to tell them apart, even with sophisticated scientific testing. Fortunately, the famous Dresden Green diamond, the largest natural green diamond in the world at 40-plus cts., has a historical record (or provenance) dating back to 1726, before the advent of artificial irradiation. Since all the literature on the Dresden Green describes the color we see today, we know its origin of color is natural.
Radiation as a physical phenomenon was discovered in the early 1900s, and the color-treatment of diamonds using radiation began around the 1930s. So documenting the gemological properties of a natural-color green diamond such as the Dresden Green provides important reference data to compare against the properties of green diamonds of uncertain origin. Eventually, such information may lead to methods of determining whether a green diamond’s color is natural or artificial.
“The Dresden Green is a large, important colored diamond whose documented history extends back several centuries,” notes Dr. James Shigley, director of the Gemological Institute of America’s research laboratory. “This diamond is gemologically important because of the information it provides in helping gemologists to solve the ongoing challenge of identifying the origin of color for green diamonds in general. With advanced spectroscopy equipment, it is possible to tell that a diamond was exposed to a source of radiation, but it is not always possible to tell whether this exposure took place in nature or in the laboratory.”
A visit to Dresden. In 1987, Shane McClure and Robert Kane, both with GIA’s Gem Trade Laboratory’s gem identification services at the time, traveled to East Germany to visit the Dresden Green Vaults (see sidebar) to examine and photograph the Dresden Green diamond. Prior to 1987, the only gemological record of the Dresden Green had been made in 1925.
In Dresden, Kane and McClure met noted gemologist George Bosshart, then of the Swiss Gemological Institute in Basel (SSEF), now with the Gübelin Laboratory in Lucerne, Switzerland. Bosshart had with him ultraviolet and infrared spectroscopy equipment, apparatus that wasn’t used to examine colored diamonds in 1925. McClure, Kane, and Bosshart spent a week at the Green Vaults under the supervision of its director, Dr. Joachim Menzhausen. The spectral data obtained by Bosshart proved to be valuable, especially because it could be compared against data from more recent green diamond discoveries.
McClure, now director of West Coast identification services for GIA’s Gem Trade Laboratory, explains the significance of the data. “The Dresden Green is a type IIa diamond. We didn’t know that before we got there. It’s very rare and difficult to separate natural green type IIa diamonds from [artificially] irradiated type IIa’s, as opposed to irradiated type Ia diamonds. It just proved that-in most cases, mind you-that the kind of spectra in natural green color type IIa’s is not helpful in separating natural and treated stones. The data didn’t give us any indication of natural or treated, and that proved to be important. If it had a been a type Ia, we would have gotten more useful information on how spectra could help us identify natural vs. treated, but there isn’t enough research on IIa’s [to do that]. The big advantage we have is knowing that the Dresden Green is natural, and our study proved that its spectra are virtually identical to treated green diamonds.”
McClure took plenty of photographs, primarily 4-by-5-in. transparencies. “The quality of the image with that format is far superior to 35-mm,” he explains. “We all felt that the significance of the piece, and actually getting permission to take it out of the mounting, demanded every effort to get the best images possible.” McClure estimates that he took between 125 and 150 shots. He also shot with 35-mm film as a backup. The visit was arranged for a time when the museum was closed for cleaning, which allowed McClure lots of freedom.
An article entitled “The Legendary Dresden Green Diamond” by Robert Kane, Shane McClure, and Joachim Menzhausen, which chronicles the history of the gem, appeared in the Winter 1990 issue of GIA’s Gems & Gemology. “The history part is what I’m very proud of,” says Kane, now president and CEO of Robert Kane & Co. Gemology, Diamonds, Fine Gemstones, and Jewelry, in San Diego. “I don’t think that you’re going to find a better history on the Dresden Green.”
A visit to Washington. The Dresden Green diamond is scheduled to be on display at the Smithsonian Institution’s National Museum of Natural History in Washington, D.C., from October 13 until January 25. It will be displayed alongside another famous colored diamond, the blue Hope. This historic event is the result of 12 years of effort by Ronald Winston, son of the late Harry Winston and owner of the Fifth Avenue jewelry house bearing his father’s name.
“I originally thought of this whole idea 12 years ago,” says Winston. “I thought we would try to do it in coordination with the opening of the gallery, the Harry Winston gallery, at the Smithsonian.” At that time, however, international political constraints made such a project impossible. But the political situation changed. “When the wall came down, things started to open up, so I went back to it,” Winston says.
Through a local Dresden jeweler, Winston was able to meet with directors of the Green Vaults. “When I arrived in Dresden, they had the Green out of the case, just by chance,” he recalls. “The director asked if I would like to look at it.” He did. “It’s enormous for a green. Even more rare than the Hope. The Hope has more history, but rarely do you get green diamonds of any intensity over a carat.”
Winston notes that Germany has been pouring huge amounts of money into the reconstruction of Dresden. “It’s a beautiful city, with its opera house, museum, and government buildings, much of which was built by Augustus the Strong in the 17th century,” he says. The state of Saxony wants to develop an international awareness of the treasures of Dresden, so Winston’s idea was well received. “After people see the Green at the Smithsonian, maybe they’ll make an effort to come see the diamond and the town,” he says.
After getting the nod, Winston asked Bob Fri, director of the Smithsonian’s Museum of Natural History, if he’d be interested in displaying the Dresden Green. Fri’s reply, says Winston, was, “Oh boy, would we!” The Green will be displayed at Winston’s New York store for one day, before traveling to Washington. The timing coincides with the Smithsonian’s millennial celebration. “The Smithsonian will now have the two greatest fancy colored diamonds in the world,” says Winston, who thinks of the conjunction of the two 40-plus-ct. diamonds as a celebration of the planet, which is blue and green. “We at Harry Winston are very happy to be a part of this great event,” he says.
On display. The Dresden Green diamond will be delivered secretly and remain under guard until it’s placed in its display case. It will be on display near the Hope diamond in the museum’s Harry Winston Gallery, the first hall inside the recently renovated Janet Annenberg Hooker Hall of Geology, Gems, and Minerals. The 45.52-ct. Hope, the world’s largest natural fancy dark grayish-blue diamond, will remain in its own secure case, and a similar case will house the Green.
There are no plans to examine the diamond up close. “We would be pretty cautious if we were to send the Hope diamond to Germany, so right now, we just want to make them feel comfortable about sending the Dresden Green to our museum,” says Jeffrey Post, curator of the Smithsonian’s National Gem and Mineral Collection.
But colored diamond authority Stephen C. Hofer, author of Collecting and Classifying Coloured Diamonds, says the diamond is far too important merely to be on display, especially considering that the Smithsonian has some top mineralogists on staff. “It will be a shame if the curators at the Smithsonian cannot examine the gem,” he says.
“They may be open to other possibilities,” notes Post. “But our major goal is to get it here safely and have it on view for everyone to see.”
The Green Vaults
Dresden Palace, which was completed in 1554, included treasury rooms-three chambers that stored silver, jewelry, and “preciosities.” The treasury rooms were called the “Green Vaults” not because they housed the green diamond, but because the walls were painted green. Locals referred to the rooms as the Green Vaults as early as 1572.
In 1945, after World War II, the contents of the Green Vaults were removed to the Soviet Union. In 1958, the jewels were returned to Dresden and placed on display at the Albertinum museum, in rooms that were given the name Green Vaults. The Albertinum occupies the former Dresden Palace, which was largely destroyed during the war. Two of the original Green Vaults, however, were left mostly undamaged. There are reports that the original Green Vaults are being renovated to again house the original contents of the treasury, including the Dresden Green.
Close Ties Between the Hope and Dresden
Found in what was probably the Golconda district in India, the Dresden Green diamond made its way to London for sale in 1726. In 1741, Friedrich Augustus II, ruler of Saxony and Poland, bought the gem and gave it to the court’s jeweler, J.F. Dinglinger, to fashion a badge of the Order of the Golden Fleece to hold the green gem. The Order of the Golden Fleece was an organization founded in 1429 to encourage virtue and faith among the nobility.
Six years after the green diamond was fashioned into a badge of the Order, King Louis XV of France set a large blue diamond into his own badge of the Order of the Golden Fleece. The blue diamond, which also came from Golconda, is believed to be the stone now known as the Hope diamond.
In 1768, when Saxony was defeated by Prussia during The Seven Years War, the green diamond was removed from the Golden Fleece badge and set into a hat ornament, where it remains to this day.
The weight of the Dresden Green is estimated at 40.70 cts., but the diamond hasn’t been removed from its original bezel since 1768, and a precise weighing hasn’t been done. When the Hope diamond, which Harry Winston donated to the Smithsonian in 1958, was removed from its mounting and weighed on proper scales, the gem weighed in at 45.52 cts.-one carat larger than had been understood from the historic literature. The same could hold true for the Dresden Green.