It looks like copper underneath because it is copper underneath.
If you take a perfectly normal US dime and punch through, scrape off or dissolve away the silver-coloured cupronickel outer layer, you will see bright shiny copper underneath. This is in effect what has happened to your coin.
Spend it if you can; I strongly suspect this coin has lost so much mass from whatever damaged it, that it is now a "mutilated coin" and no longer legal tender.
If you take a perfectly normal US dime and punch through, scrape off or dissolve away the silver-coloured cupronickel outer layer, you will see bright shiny copper underneath. This is in effect what has happened to your coin.
Spend it if you can; I strongly suspect this coin has lost so much mass from whatever damaged it, that it is now a "mutilated coin" and no longer legal tender.
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