What's that yellow-green halo over there coming towards you? No need to run in fear, it's just luminescent zinc sulfide here to shed some light on the situation.
Luminescent zinc sulfide sounds like a ghost story name but it's simply a phosphorescent powder, made with a zinc sulfide combined with a copper additive. Here's something to zinc about, after a day spent absorbing the energy of natural or artificial light thanks to copper (your soul is safe!), it will glow in the dark to better haunt your dreams (and helps you find the soap if you forget to pay the electic bill!).