I'm not sure what this is - maybe a Belgian 20 centime? It's only 12.5mm and looks to have been dug up, so please pardon the picture quality.
I don't know that coin in particular, but Lauer Nurnberg did many replica miniature coins. http://www.ebay.com/itm/Miniature-U...438?pt=LH_DefaultDomain_0&hash=item4d01f640be
Ah - so it's a contemporary miniature? Interesting. What purpose did these serve? The eBay link says something about the miniatures being for reference by counter clerks... but that doesn't make much sense to me. Why would you need a miniature rather than just setting aside one of the actual coins? It doesn't seem like the miniatures would cost less to make than that.