Copper has been worn for centuries, both for its great beauty as well as its purported health benefits and antimicrobial properties.

In Greek mythology, copper was thought to be the metal of the goddess Venus. 
Copper is the main metal used in making bronze and is used as an alloy in traditional sterling silver (Argentium sterling is not alloyed with copper) as well as certain kinds of gold such as red gold and rose gold.   
When wearing uncoated copper,bronze,sterling silver or copper alloyed golds close to the skin,(such as a ring) the copper can react to environmental factors combined with an individual’s body chemistry.   
For example, if your skin ph tends to be more on the acidic side than the alkaline side
(some people report that this may have to do with stress,diet or a particularly hot day!) or if you have worn your ring in a salt water bath, you may see a green or bluish skin discoloration where the metal meets the skin.    
As far as I know, this is not harmful and can be easily washed off with soap and water or be absorbed by your body overnight. 
Many people experience no discoloration.

Sealing or Coating your metal is an option if you experience discoloration.  

I prefer NOT to coat the copper pieces that I make (unless someone asks me to) because many people prefer the bare copper to skin contact.

Some people report that simply keeping their metal clean by washing it with soap and water daily,(or plain toothpaste to bring out shine) prevents any skin discoloration.

Some of the methods that people use for coating or sealing metal in order to create a barrier between the skin and the piece are as follows:


Clean the piece of jewelry by either washing with soap and water,or by wiping with rubbing alcohol. Dry thoroughly.
Coat just those areas that touch your skin with one of the following:*


1.   Jewelry wax, car wax, or any wood wax appropriate for metal. Applied and buffed according to instructions.  


    * I recommend these eco-friendly, solvent free, paste waxes:

      a) Doctor's Woodshop Walnut Oil Paste Wax   ( made with a very hard, plant-based wax called Carnauba ) 

      b) Doctor's Woodshop Walnut Oil Microcrystaline Paste Wax   ( especially made for metal )

2.    A thin sprayed-on coat of a clear acrylic lacquer.  

       When this starts to wear off, remove old layer before re-applying.

       ( not eco-friendly. I don't recommend it )


3.    A thin layer of clear nail polish.

       Re-apply same as above.

       ( not eco-friendly. I don't recommend it )