Copper Oxidization: The Natural Process
Copper naturally reacts to it’s surrounding environment and will change color over time due to the exposure of the elements such as oxygen, water, heat, and pressure. Copper darkens, browns, or can develop green/blue patina spots. No two pieces will age the same.
The Mother Nature pendant on the left side of photo is the original sample. It's been exposed to the elements for about 2 years. The one on the left is brand new.