1965 copper quarter

There are a few things that might have happened to your quarter. If it seems smaller or parts of the coin are missing and looks uneven, it could be struck on a blank intended for a penny. If all the details are there and the coin looks normal only the fact it is copper, there are a few things that could have happened. The first thing is post-mint damage, someone could have plated your coin with copper. The second possibility is that your coin be lacking the nickel cladding, this is very possible and is a documented error. Now, when it comes to value, it is impossible to really say. The first thing you need to do is figure out what type of error it is, once you have figured that out, you can then see the value of it to find out how much it is worth. Keep in mind though, errors are often times harder to sell because there are fewer error collector than people who collect mint-state coins.