I love copper jewelry. The rusty red-browns go great with almost everything. I think copper looks especially great with swimsuits. Looks fabulous with your tan! I have alot of great pieces. Unfortunately after short honeymoon, my piece would tarnish and turn my skin black. The natural acids in our skin, hand lotions and other chemicals can quickly make copper jewelry oxidize and turn our skin black.
Here is how I keep my skin and my copper pieces looking great. I would not try this, however, with pieces that have stones, rhinestones or beads do not use this methods. Also if you have an heirloom piece, I don't suggest risking damaging it.
I use two different methods of treating my copper jewelry. For example, I have a copper and brass bangle bracelet that I love. I used clear nail polish to coat the entire inside of the bracelet. I used two coats to be sure that I'd have a good protective barrier. Be sure to allow to dry before you put on your jewelry. The nail polish will wear off over time, so you will have to re-apply once the discoloration reappears. This methods works great for rings too.
Another method uses spray paint. Suspend your piece in a cardboard box and spay a couple of thin layers of clear spray paint. This methods works great for earrings, barrettes and necklaces.