I found a montana quarter that appears to be copper. Even feels lighter than standard quarter. Any ideas?
First, welcome to the neighborhood! People often post coins that are missing a clad layer, but without photos, it will be hard for us to tell if they truly are or just damage. Here is my favorite that I found in a Mint bag. Chris
That'll be a nice find if it is indeed missing a clad layer and not a coin that's been acid etched or whatever.
If it's copper colored on both sides, and the reeded edge is fully copper, then it's been copper-plated.
The vast majority of "missing clad layer" coins posted turn out to be just environmental damage. But missing clad layers can happen, so the best thing to do is post pictures AND an accurate weight for the coin to one or preferably two decimal places.