When it is exposed to air, it darkens or tarnishes, forming what is commonly referred to as copper “patina.” After prolonged contact with human skin where it can interact with air, sweat and other chemicals, such as soaps, lotions, and makeup, copper can turn green or bluish-green, and stain the skin in the process. At Lexi Butler Designs we put a hypoallergenic top coat on all nonmoving parts. For more info please please refer to our Jewelry Care Guide