The above posters are correct; these are brass imitations of 19th century Ottoman gold coins. I the Near and MIddle East, such coins are used for jewellery and other decorative purposes - when I was in Turkey a couple of years ago, I saw similar coins being used to decorate the tassels on the traditional sherbet-sellers walking around the Grand Bazaar in Istanbul - but "belly dancer coin" is a convenient shorthand.
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