Pure copper is allergy-safe, though since it is so soft, it may be alloyed with nickel when is is made into jewelry. If you can be certain it has not been alloyed with nickel, it’s lovely to wear. Enameled or oxidized copper is generally fine, though be cautious of “antique” plating, as I mentioned under Brass and Bronze.
Can you wear brass jewelry in the shower?
Brass or bronze jewelry will tarnish more quickly than sterling silver, but can easily have its shine restored. We recommend that you do not wear your jewelry in the shower, hot tub, sauna, ocean or swimming pool, as moisture accelerates the tarnishing of metal.