It weighs right and looks right. I just need another person to look at it. Caesar (Octavian) Augustus Date: 29 BC - 27 BC Denomination: Denarius Mint: Uncertain value Obverse: Head of Octavian, bare, right Reverse: IMP CAESAR: Terminal figure of Octavian, placed on thunderbolt Weight: 3.81 grams Diameter: 15 mm Heres an authentic one for a reference: Now let me know what you guys think on this one. If everything checks out, I'll be making some big money. Heres the two coins side by side and some higher quality images that aren't edited: View attachment 1021935
I'm by no means an expert. That being said, the coin in question doesn't look right to me. I will wait for other, much more knowledgeable, people to chime in with their assessments.
There is an example of this coin being sold on Ebay by a seller that is listed on NFSL. I'm not sure I would trust the OP coin any more than the one selling on Ebay.
Update: The coin is 21 mm I measured totally wrong. Sorry for the confusion. And the coin does have some natural spots and patina. And those won't come off so I'm guessing those are natural. (And no, I didn't clean it.)