Even if it were genuine, coins are almost never "worth popping out". A coin is usually badly damaged by the process of mounting it into jewellery. Breaking it out will just result in a "damaged coin, ex jewellery mount" and worth only a tiny fraction of the value of an undamaged example; it is usually worth more as an intact piece of jewellery.
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