So you went out and bought a pair of shiny new earrings or a fabulous necklace. They look pretty good on, but after wearing them for only a few hours, your ears or neck start to feel irritated. At first, it might not be bad, just slight redness where the jewelry touches your skin. But eventually, it gets worse and turns into a skin rash. You notice that the skin rash has turned green; the jewelry is to blame. So you take off your new earrings and necklace. Before putting them back in their packages, you want to ensure they aren't defective. So what's causing this skin reaction to jewelry? How can you prevent it?