N.W.T.'s Foxfire diamond glows brightly on international stage

The Northwest Territories' biggest diamond find has been enjoying a marquee run at the most popular museum in the United States.

The 187.7-carat Foxfire diamond the largest diamond ever found in North America is on display at the Smithsonian National Museum of Natural History in Washington D.C.

"People have been very excited to see the diamond and we've certainly enjoyed showing it to them," said Jeffrey Post, curator of the National Gem and Mineral Collection at the museum.

Found at Diavik diamond mine in 2015, the gem was sold for an undisclosed amount last year.

• N.W.T.'s Diavik mine yields one of Canada's largest diamonds

The owner of the massive uncut diamond has loaned it to the Smithsonian, to study and display to the public, until April.

"Most diamonds get sold into the gem market. They get cut, they get polished, and get put in jewelry," said Post.

"People are sort of reluctant to have scientists poking and prodding at their big gem-quality diamonds. So when we have one that comes to us in the rough form like this... that's a really special thing for us...and as museum scientists we get to share the diamond with the public, so it's the best of all worlds."

Blue glow under UV light

The diamond gets its name from Dene descriptions of the northern lights as a flickering foxtail. Based on observations made by Post and his team, the colourful name suits the stone well.

One way to examine the physical properties of a diamond is to bathe it in ultraviolet light.

"When the Foxfire came in, we put on the ultraviolet light, and it just lit up the vault bright blue. I mean it is a bright, bright blue fluorescing diamond," said Post.

"When we turned off the ultraviolet light, the bright blue fluorescence stopped, but the diamond continued to glow in the dark a sort of light orange, a peachy orange colour."

He said the glow likely has to do with trace amounts of nitrogen contained within the diamond.

"If your eyes are adjusted to the dark, and you're in a dark room, that phosphorescence lingers on for several minutes. In fact, we've never actually seen it stop. We just finally get tired of watching it, and just go away."

Educating the public onCanadian diamonds

Beyond the joy of studying and displaying an exquisite diamond, Post said he has enjoyed using the diamond to teach visitors about the Canadian diamond industry.

"Most of the visitors coming into the Smithsonian and our museum gets somewhere around six to seven million people a year they still don't realize that Canada is major producer of diamonds," he said.

"It's just something that people have not really, for whatever reason, learned about. So to tell somebody that here's this large diamond that came out of Canada, and by the way Canada is one of the largest producers of diamonds in the world... they just look at you with their mouth half open going, 'Oh my gosh, I had no idea.'"