Several weeks before it went on display in mid-November at the Smithsonian’s National Museum of Natural History, minerals curator Jeff Post stood in the museum’s secure gem vault with this very large and very strange diamond in his palm. He motioned for the lights to be switched off just as he flipped on a long-wave ultraviolet lamp.
“Diamonds can have some interesting properties if you expose them to UV,” Post said.
This particular diamond doesn’t look like a normal gem. For one, it is rough, still in the same uncut state in which it was unearthed in August 2015 at Diavik Diamond Mine in the Barren Lands of Canada’s Northwest Territories, approximately 130 miles from the Arctic Circle. For another, it is enormous: at 187 carats, it’s the largest gem-quality diamond ever discovered in North America. If you didn’t know any better, you might easily mistake it for a chunk of ordinary glass.
http://insider.si.edu/2017/01/diamonds-eerie-glow-earns-fiery-name/Related (Old article): Bombarded with ultraviolet light, the blue Hope diamond glows red.
http://insider.si.edu/2009/08/blue-hope-diamond-glows-an-erie-red-after-exposure-to-ultraviolet-light/
