But It Can't Be Real

I did forget to mention that the legend reads Diocletian.

I would have to defer to your knowledge of Roman bronze coins. I don't know on this one.

But the fact that it appears to be 'copper' makes me suspicious.
I was certain it was genuine ........ at first
But when I added up all the peculiarities I began to doubt.

I would love to proven wrong !
In fact I posted it as fake hoping someone might persuade me otherwise.

I remain ......... Uncertain !

I have a theory, but think I'll wait to see what others come up with first

I have a theory too Ian !

I think the same joker who made the bearded Nero asses is having another laugh !
The coin is copper as far as I can determine. As I have mentioned before I live adjacent to one of the best Polytechnic schools in the US.
It's about time I checked to see if I can interest any grad students in Roman metallurgy.
Copper makes no sense at all to me. The maker of this may well have an unusual sense of humor.

As far as I can see the mark is P T with nothing missing.

It's genuine. Issued post death. Posthumously, they earned God status. No reason to fake a coin like that and add a patina, and so on. Nice coin.

Once again I have swung to the opposite extreme.
As Athalbert and 'Ian' have so confidently endorsed the coin, and my wise old owl brother is still trying to relieve me of the burden of owning it !

I am now of the opinion that it is "good". The fact that the seller asserts that it was actually found in situ with the coins which it came with certainly helps too !

My major objection was/is the composition.
But my brother has made a necessary connection. I had spoken of how the edges reminded me of a copper As of Claudius.
The connection ?
He opined that this follis was probably overstruck on an As of that period !

The only real test left is to see if I can interest a student at the Polytechnic here in Worcester to compare the alloy. If it can pass such a test then the coin not only makes the grade ....... It makes it too the head of the class !

I suddenly had a 'brain storm' !
But now that I feel better another (remote ?) possibility occured to me.
As many of us know (a few anyways) late 3rd century there had been repeated attempts to bring back the glorious good old days.
Note that this coin does appear to have been struck upon a flan which may have been dented with a "ball-peen" hammer. In particular the obverse 10-12 o'clock. Now checking my handy Sear what do I find ?

Number 12830 ! Bronze reduced sestertius ! This was a pre-reform attempt to continue the efforts (starting with Aurelian) to reintroduce the old denominations. A possible lead may be finding the specific weight and diameter (Sear gives 24-5mm) of this reduced bronze sestertius. Might the mint have as part of the recall of pre-reform coins simply hammered the bronze issues and reminted them with the follis dies at hand ? Possibly this happened at the very start of the new follis denomination (explaining the curious portrait style ?).
A hammered flan might explain the large diameter 28-30mm and seems evident in the curious marks on the obverse. Additionally it seems possible that irregularities in the fields may be from the previous image now all but obliterated.

I need find a bronze "sestertius" of Diocletian to compare.
Ian you are great at finding such details. If we both search perhaps we might find the answer.

One last thought
The coin when 'new' must have been a bright copper color.
Perhaps the cuirassed bust was used to indicate a separate lesser value ?
Having no silver content it would have been less desirable.