Copper is found in a variety of jewelry such as rings, necklaces, and earrings, and is one of the biggest and most common culprits of skin greening. Other guilty metals include nickel and, sometimes, sterling silver.
The green on your skin is the result of oxidization, a chemical reaction caused by your jewelry’s metal reacting with oxygen and acids from your skin. This process is very natural, as your body produces slightly acidic sweat.
Cosmetic products such as hand lotion, soap, and perfume can also react with your jewelry and speed up the oxidization process. To avoid this, make sure to wash your hands thoroughly before wearing jewelry.