Because this vial contains tritium, a radioactive form of hydrogen, it is a very unusual keyring guaranteed to start a conversation. It does indeed glow, not bright as a flashlight but plenty to notice in the dark. I got this as a gift for a friend who teaches earth science, and he likes it a lot. He shows it to his students to indicate how tritium, decaying from its radioactive state and energizing a phosphor, can make a glowing light. Not to worry about it being radioactive -- tritium's energy state is a very low beta, not strong enough to penetrate the dead outer layers of skin so it's perfectly safe. Only the light escapes the acrylic cylinder, and it's very fascinating to study. Plus, tritium is one of the rarest things on earth, far more rare than any precious metal, so having even this tiny amount is scientifically appealing.

Because this vial contains tritium, a radioactive form of hydrogen, it is a very unusual keyring guaranteed to start a conversation. It does indeed glow, not bright as a flashlight but plenty to notice in the dark. I got this as a gift for a friend who teaches earth science, and he likes it a lot. He shows it to his students to indicate how tritium, decaying from its radioactive state and energizing a phosphor, can make a glowing light. Not to worry about it being radioactive -- tritium's energy state is a very low beta, not strong enough to penetrate the dead outer layers of skin so it's perfectly safe. Only the light escapes the acrylic cylinder, and it's very fascinating to study. Plus, tritium is one of the rarest things on earth, far more rare than any precious metal, so having even this tiny amount is scientifically appealing.

Because this vial contains tritium, a radioactive form of hydrogen, it is a very unusual keyring guaranteed to start a conversation. It does indeed glow, not bright as a flashlight but plenty to notice in the dark. I got this as a gift for a friend who teaches earth science, and he likes it a lot. He shows it to his students to indicate how tritium, decaying from its radioactive state and energizing a phosphor, can make a glowing light. Not to worry about it being radioactive -- tritium's energy state is a very low beta, not strong enough to penetrate the dead outer layers of skin so it's perfectly safe. Only the light escapes the acrylic cylinder, and it's very fascinating to study. Plus, tritium is one of the rarest things on earth, far more rare than any precious metal, so having even this tiny amount is scientifically appealing.