The largest gem quality diamond ever found in North America is on display at the Smithsonian in its rough, uncut state until February 16. The 187.63 carat diamond is being displayed at the Smithsonian’s National Museum of Natural History in the Harry Winston Gallery. The gallery is also home to the 45.52-carat Hope Diamond.
Side note – The Hope Diamond was once a symbol for Louis XIV, the Sun King.
Discovered at Canada’s Diavik Diamond Mine in August 2015, the Foxfire is the biggest diamond ever known to be found in North America.
“It’s a really unusual chance for people to see this rare diamond,” says Jeffrey Post, curator of the National Gem and Mineral Collection at the Smithsonian’s National Museum of Natural History. “It isn’t something that happens very often. This may be the only chance in your life to see such a thing.”
Diamonds tend to be highly concentrated in small areas underground where ancient volcanic eruptions pushed magma upward through tubes. The magma solidified into an igneous rock called kimberlite. Scattered through the kimberlite left within the tube are diamonds that were pushed upwards with the magma.
The 187.63 carat Foxfire diamond was almost discarded when it was unearthed in August 2015 at the Diavik Mine, which is above the Arctic Circle in Canada’s Northwest Territories. The mine is not known for large diamonds like the Foxfire. The chances of a large diamond coming through the sorting system were believed to be so slim that all large stones were assumed to be kimberlite, thus filtered and crushed. The Foxfire diamond could have been crushed, but because of its somewhat elongated shape, it slipped through the sifting screen.
The name Foxfire pays homage to the aboriginal name for the aurora borealis, which Post says looks like “foxtails swishing away in the sky.”
Photo by Donny Bajohr for the Smithsonian.
In June 2016, Deepak Sheth of Amadena Investments, who trades in historic or unique stones, purchased the uncut diamond at auction (the exact price has not been publicly disclosed) and then did an unusual thing. He allowed the Smithsonian’s scientists to borrow it.
“In some way, it’s like diamonds are like meteorites from deep in the earth,” Post says.
Most diamonds appear to have been created between one and three billion years ago roughly a hundred miles beneath the surface of the Earth. Diamonds can help geologists understand Earth’s history, says Post.
During past volcanic eruptions, “diamonds were brought to the surface, giving us a glimpse into a part of the Earth we can’t otherwise study,” Post says.
In order to find out more about the Foxfire diamond’s composition, Post exposed the uncut gemstone to different types of light and used a spectrograph to see how the various elements in the diamond were reflecting the light. A funny thing was discovered along the way.
“One of the interesting properties of this diamond is that if you go in a dark room and turn on a UV light, it glows bright blue. It lights up the room,” Post says. “There are a number of diamonds that do this, but this does so quite a lot. This happens through trace amounts of nitrogen. By doing spectral analysis of that light, we can tell how much nitrogen might be there.”
Photo by Donny Bajohr for the Smithsonian.
It gets weirder.
“What is unusual, is that when you turn the light off [the diamond] continues to glow. First a deep orange color and then it fades to a creamy white glow. So that phosphorescence can tell us something about how that diamond was formed. . . . It gives us this interesting insight into its history that we wouldn’t get just by looking at it.”
“We’ve never actually seen it stop. We just finally get tired and walk away from the diamond,” he joked.
Post said he’s never seen a diamond that fluoresces so blue and then phosphoresces so orange. They are studying the Foxfire while they have it to get a better idea of what it means and “really, what’s going on inside this diamond.”
He also remarked on how this big rough diamond fits into the museum’s mission of educating and creating an experience for its visitors, saying, “How often do any of us get to see a large diamond that’s been found and mined anywhere in the world, and the public – never. This is a once in a lifetime opportunity for most of our visitors.”
The Foxfire Diamond will remain on display at the Smithsonian, housed in a glass case just feet from the Hope, until February 16. After that, Sheth plans to take it on a “world journey” to share it with other admirers.
*Cover photo courtesy of Rio Tinto.