I've had this coin for years and I had suspected that it was fake but I finally got around to confirming it. I bought this in the early days of collecting when I was trying to complete date sets as cheap as possible. I remember that the listing even said it was magnetic but I thought, "50 percent silver - maybe that's why." I tried just now and yes, it's definitely magnetic, and the weight is 17g when it should be 28.28g. What's odd is it's not a particularly rare coin. I can get one on eBay today for about $30, and at the time I bought this I'm sure it was less. I feel like I paid around $10 for it and I think it was from Europe, maybe Hungary. I just wanted to share mostly because it doesn't seem like a typical coin you'd expect to be faked.
It's always a mystery to me why people bother faking coins you think wouldn't be worth the effort. Unless it's just practice before they work their way up to more valuable coins to fake.
It's possible it was faked back in 1949 or shortly thereafter in order to spend it, just as recently Britain has had a lot of fake pounds to contend with. A crown was a lot of money in 1949.
It might have cost less than 1$ to make so there could have been a huge % profit. That's all the incentive needed to fake coins that aren't rare.
Didn't immediately occur to me, but yes it's possible it was a contemporary monetary counterfeit, meant to be spent, rather than a fake meant to fool collectors. At the time if it could be produced for less than the coin pretends to be worth, it would be worth the effort to fake it. Reminds me of the supposed "micro O" Morgan dollars PCGS mistakenly thought were a newly discovered variety of New Orleans minted Morgan dollars. They even certified a few of them, but on closer examination they were discovered to be counterfeits made sometime in the 1940's (kind of an embarassment to them, but they offered refunds to anyone that paid for certification of these, and declared they would no longer certify the micro O "variety.") Ironically, they actually had too much silver in them; some of them were up to about 94% silver rather than the 90% they should have been (they also oddly had other metals like tin and lead in them). In the 1940's that much silver was worth less than $1, so it was worth the effort to fake. In Ecuador, that uses the US dollar now, ever since hyperinflation of the Ecuadorian sucre, they've discovered counterfeit Sacagawea dollars. The portrait of Sacagawea was often amusingly cartoonish; I guess they assumed nobody would look at them that closely (or just weren't that good at copying the portrait). Some of them have made it back to the US. So TLDR version: not all counterfeit coins are made to fool collectors; some are just meant to be spent.
Even the ancient Greeks counterfeited money to be spent. There were no collectors that I know of when the Phoenicians counterfeited my "Athenian" tritartemorion. And not all those cut marks on ancient electrum, gold, and silver coins were for decoration.
This would not likely pass with that much of a weight difference -- much more likely to be a fake to fool collectors.
I would presume after this much time that many contemporary (to the time the real thing was originally produced) counterfeits would be almost as collectible as the real thing. Not sure precisely when the hobby of coin collecting got started, but from what I've read the hobby is almost as old as coins themselves. Reasonably well off Romans were fond of collecting Greek coins before they were old enough to call "ancient" yet.
Not impossible, but not all fakes are good fakes. Maybe they were hoping nobody would examine it closely, or maybe they just weren't good at making a passable fake (to be fair, it passed for this long, so...). The thing that makes me lean towards spending fake rather than collecting fake is that it's not a particularly valuable coin today to make it worth faking. (I concede that doesn't necessarily prove anything; I myself have a fake Chinese coin that would only be worth about $15 today if it were real.) I don't know 100% that it wasn't made to fool collectors, but it's not what I'd put my money on.