I assume the box, and little circle opposite the box, would be where you'd attach a brooch-style mount if you wanted to turn it into a badge rather than a button.
If that's right, then this piece would have been deliberately made as "imitation coin" 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