Uranium glass collectibles glow. But don’t worry, they’re not toxic.

While roaming my favorite antique store outside Atlanta recently, I heard a “click click” sound and turned around to see a woman shining a black-light flashlight on a green plate. A few minutes later, a man joined her with a black box that began to hum when it got close to the plate. It was the unmistakable sound of a Geiger counter, a tool used to detect radioactivity. Like me, they were in search of a specific kind of vintage treasure: the green glow of uranium glass.