what causes ring finger to turn black
Discoloration where a ring touches your skin is due to a combination of factors: the metal of the ring, the chemical environment on your skin and your body's immune response to the ring. 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.