Help ! Unidentified Coin

First of all NEVER put a coin in any corrosive or acidic liquid (i.e. coke) as it can severely damage a coin and never clean a coin, polish it or wipe it harshly even if it is ancient, rusty, etc. Only use substances recommended by professionals for treating a coin. Sorry to be so harsh but it is important to lay down those rules in numismatics. Luckily enough it probably already looked like that before, so it's probably not gonna really affect it.

Anyway, that's quite a cool find. And yes it is quite large and heavy. Unfortunately, I'm not really great at uncovering the details of ancient coinage nor can the photos depict much detail, try taking closer pics, under a light at an angle, thanks