It's likely been plated in something. I also have heard that coins coated in mercury will get a silvery appearance, though I haven't seen it myself.
If it were a post-1982 cent, there's the chance it could have been struck without the outer layer of copper plating, showing only the zinc core, which has a silvery color. But since your coin is dated 1980, that isn't possible, as 1980 cents had no zinc core- they were struck in solid copper (bronze, actually).
Comments
"Looks like a nickel", how? Of course it'll be a little smaller than a nickel.
If it were a post-1982 cent, there's the chance it could have been struck without the outer layer of copper plating, showing only the zinc core, which has a silvery color. But since your coin is dated 1980, that isn't possible, as 1980 cents had no zinc core- they were struck in solid copper (bronze, actually).