A good tip to all fashion-jewelry owners is to keep your ring away from water or other substances that may cause a negative reaction of the jewelry with your pH levels (tarnishing, greening of the fingers, etc).
Another neat tip is to create a barrier between your skin and the ring by coating the inside of your ring with clear nail polish. This should help extend the life of your jewelry pieces!
With proper care and cleaning, the rings should not turn your finger green. Please keep in mind that pH is the main cause for jewelry causing skin to “turn green”.