That is a blatant cast piece. I don't think I would call it a copy. More like a token or something you would pick up in a gift shop. Not a coin.
First, welcome to the neighborhood @Miles Holmes ! It definitely looks fake to me, too! It might be a good idea if you bought yourself a copy of "A Guide Book of United States Coins", commonly referred to as the Red Book. Although I don't recommend using the pricing, the book does contain a wealth of information about every coin that has ever been used or produced in the US since colonial times. It is published by Whitman Books and is available on their website. Chris
Thanks, it may help me to go further. Well, I wish I knew too, that's why I asking questions here; I'd found it during a repair in the house in East Europe.
There isn't enough detail left for me to tell whether it was an imitation $2 1/2 or $5 coin -- if it's about the size of a dime, it's an imitation quarter-eagle ($2 1/2); if it's about the size of a nickel, it's an imitation half-eagle ($5). (Are you familiar enough with US coins to know about dimes and nickels? I shouldn't assume...) It might have been gold-plated at some point, but if so, that's worn off now. Definitely not "real", and probably not worth anything, but an interesting thing to find in an East European house all the same. Welcome to CoinTalk!
A copy of a US Gold coin. Totally fake but maybe worth a couple to bucks to a collector of these things.