I picked up this today, it was labelled as a silver coin of Nader Shah (1736-1747) with no other information, and I've been trying to figure out a more specific identification, but can't find any coins that look like this, the (visible) text and the plain circle in that second picture don't seem to match up with anything listed for Nader Shah I can find, which makes me wonder of it could have been misidentified, and could be from a different Iranian ruler or dynasty, or possibly from another country like Afghanistan.
The weight is 4.6g (so if it is Iranian, it's probably an abbasi), and the diameter is 17mm

