Not sure on the ID, but that light green stuff looks like it could be bronze disease. See if it’s powdery. If it is, a week or so in distilled water should take care of that.
I would guess Attica under Roman rule. You are showing the reverse first. The obverse is clearly Athena wearing a Corinthian helmet. More info needed though, size, weight, where it came from etc. That coin has had some bad bouts with bronze disease and it has come back. If it is not already please get it in distilled water!