Bright copper has a lustrous shine and will darken over time. Copper can easily be cleaned back to a bright shine. Just wipe with a jewelry cloth to brighten it up again.
Antique copper is treated to speed up the oxidization process that occurs naturally. It may brighten as you wear it when it reacts to the oils on your skin.
Copper may cause skin discoloration with some (not all) wearers. This is a known reaction with copper jewelry. Copper pieces are not treated in any way so you can benefit fully from its healing and health properties. That being said, lacquer coating can be applied for an additional $5 for those that would prefer it.