Halloween is the busy season for Whitney Granger’s glow-in-the-dark jewelry business.

But we’re not talking about the cheap, plastic glow-stick-type of goods that light up for just a few hours before fading. Rather, Granger is a collector of rare, vintage uranium glass jewelry, which, even in the daylight, has a subtle glow. But the real party trick happens under a black light, when the rings, necklaces and brooches in her curio cabinet glow so neon green that they almost seem supernatural.

“People are like ‘Ooh, I like your ring,’ and then you can say ‘watch this,’ and pull out a black light and show them how it glows. It has this neon quality to it that makes it pop,” said Granger, a Longmont jewelry artist who sells uranium glass jewelry on her Etsy shop StoryShapedStudios and often wears the necklaces, bracelets and rings from her own 150-piece personal collection.

During spooky season, Granger said, there’s a niche group of uranium glass enthusiasts who wear the jewelry to black-light dinner parties. Hosts pull out their fanciest glow-in-the-dark vintage glassware.

Wow factor aside, people are, of course, curious: “Is uranium glass safe?”

Paul Frame, a senior health physicist who specializes in radiation protection and who started Tennessee’s Oak Ridge Associated Universities’ uranium glass collection in the 1980s, said it’s completely safe.

“There’s no real risk at all,” Frame said. Though the uranium levels you’d find in glass collectibles are innocuous, he said, there will inevitably be those who will never be convinced otherwise — which could have something to do with sci-fi movies, he said. For what it’s worth, we’re exposed to low amounts of radiation daily, Frame explained. Even bananas have low levels of uranium, though you’d have to eat 100 of them to get the same amount of radiation exposure as you would get each day in the U.S. from natural radiation in the environment, according to the Environmental Protection Agency.

The EPA points out that antiques containing radioactive material may emit “very low levels of radiation for thousands of years, if not longer.” And we’ll sound like Halloween party poopers here, but the EPA does warn against eating off of vintage uranium Fiestaware to avoid ingesting any chipped pieces.

So how did uranium come to be in collectibles? A popular colorant used worldwide, uranium peaked in popularity in the United States between 1958 and 1978, when more than 4 million pieces of decorative uranium glass were manufactured, according to the Oak Ridge Associated Universities’ Museum of Radiation and Radioactivity.

This has led modern-day collectors on treasure hunts, armed with black lights, searching thrift stores, antique shops and estate sales for dinnerware, drinking glasses and other items (like marbles) made with the chemical element.

But even more niche is collecting uranium glass jewelry. In fact, when Granger stumbled upon her first piece on eBay a few years ago — a pre-World War II Czech flapper-like beaded necklace from Neiger Brothers — “it was love at first sight,” she remembers. But she could hardly find any information on uranium glass jewelry. She was hooked, and started a Facebook group called Uranium Glass Jewelry, which has grown to more than 5,600 members. Collectors show their finds, with photos of brooches and beads, rings and necklaces, often pictured showing what it looks like in natural light and under a black light.

“Not to toot my own horn (but I totally will). I consider myself responsible for starting the interest in uranium glass jewelry,” Granger said. She’s  not wrong: The demand for vintage uranium glass jewelry has grown so much that her hobby transitioned into a full-time job coming out of the pandemic. In addition to collecting pieces to sell, she also sources vintage uranium glass to craft jewelry for her Etsy shop.

The prices of pieces vary, but a collection of five brooches, for example, sold for $45. Earrings start around $25 and rings can fetch $200 to $300 or more.

She certainly understands the allure of finding the jewelry: “You take your blacklight, you go hunting, and you never know what you’re going to find. Our brains are addled by the green glow,” she said.

One of Granger’s most treasured finds that feels apropos for Halloween? A 1830s Georgian pinchbeck choker. It would have originally been on a bracelet made of … woven human hair, she said. How ghoulish.