It cannot be "part of the coin", because being a pre-1982 cent, this coin is made of bronze; it does not have any silvery metal inside it to "break out". The piece of silvery metal must therefore be attached to the coin's surface in some way. If it appears to be stuck there fast, then it's probably solder.
Don't say "infinitely" when you mean "very"; otherwise, you'll have no word left when you want to talk about something really infinite. - C. S. Lewis