It's a common misconception that only cheap rings can turn your finger green. Inexpensive rings commonly are made using copper or a copper alloy, which reacts with oxygen to form copper oxide, or verdigris, which is green. It's not harmful and wears away a few days after you stop wearing the ring. However, fine jewelry also can cause discoloration of your finger.
Silver rings can turn your finger green or black. Silver reacts with acids and air to tarnish to a black color. Sterling silver usually contains about 7% copper, so you can get the green discoloration too. Gold, especially 10k and 14k gold, usually contains enough non-gold metal that it can cause discoloration. White gold is an exception, since it is plated with rhodium, which tends not to discolor. The rhodium plating wears away over time, so a ring that initially seems fine may produce a discoloration after it has been worn a while.
Another cause of discoloration may be a reaction to the metal of the ring. Some people are sensitive to any of a number of metals used in ring, especially copper and nickel. Applying lotions or other chemicals to your hand while wearing a ring increases the likelihood that the ring, chemical and your skin will react... Learn more