Basically you can't ID it. You have no Obverse Legend to base an ID on. All you have is size, weight & head type which will narrow the timeline but never give you an Emperor. The Reverse will narrow it a bit further, anything on the back?
So, far its late 4th C AD.
Hi Crus. One thing that makes me think it's a roman coin is that near the site i've found the old bronze ring( i've posted it before).
Also Quicksilver reminded me the roman minis and it looks the same
In the back i can notice nothing and im afraid to clear it.
If i remove the patina i'm afraid there's nothing left.