For it to be that color it’s damage by the environment. It was lost and found but it spent time in the ground.
The "silver" colored layer is the clad layer made of Cupro-Nickel. The copper mixed with the nickel tones/darkens when exposed to the elements. Here are many of my own Metal Detected examples on clad coins and Nickels..
Not always. Sometimes the Coinstar will reject the Environmental exposed clad coins. I've had that occur many times
