Help Identifying A Coin Please

i would like help identifying a coin please as I'm not a collector and know nothing about coins.

my partners father passed away in ireland last year and we were sorting through a load of old irish coinage he had stashed away recently which we are going to change at the bank in Dublin.
Amongst the coins, we found something that looks a fairly old.
I don't know what country it's from or what it is at all.
I would be gratefull if anyone could shed some light on what this coin is or where it could be from.

Some of the corrosion on it looks like copper corrosion, but I think thats just because it was in a bag with a lot of old copper coins. there is the odd area where the surface appears to have been worn away a little and I can see the metal underneath. it doesn't quite look like silver or gold in colour, more sort of in between the two if that makes any sense

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and finally one for size:-
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