This is a Maximian radiate. Obverse legend, IMP C MA MAXIMINVS PF AVG. Reverse legend CONCORDIA MILITVM.
It looks like a post-reform radiate of the emperor Maximian. The type of thing in uncleaned Roman lots sold by the kilogram. Worth a dollar or two, perhaps.
That's a "radiate fraction" minted for the emperor Maximian in the late 3rd century AD, for further details see here. It's historical value is great – this is a 1.700 year old witness of one of the crucial periods in Western history. Yet, in this poor state of preservation, its financial value is rather minimal. For comparison, I paid less than $10 for the coin of Maximian's colleague Diocletian below, and it is in much higher grade than your example. Diocletian, Roman Empire, radiate fraction, 295–299 AD, Cyzicus mint. Obv: IMP CC VAL DIOCLETIANVS PF AVG; radiate, draped, cuirassed bust of Diocletian r. Rev: CONCORDIA MILITVM; Jupiter standing l. and holding sceptre presents Victory to emperor standing r.; between them, mintmark KΓ. 22mm, 3.2g. RIC VI Cyzicus 15a.
Perhaps the obverse is double struck...OR...jugate busts! If the latter, CNG mentions : "Trier struck folles with three unique jugate bust types in this period; Maximianus and his patron god Hercules, the two Imperators Diocletian and Maximianus and the two Caesars Constantius and Galerius." I can't tell if this is from the Trier mint, but perhaps this is Maximianus and Hercules. Pure speculation on my part....because of the seemingly jugate busts. Something for you to check.
I'm far from a late Roman bronze expert but I think Pete's observation warrants investigation. It really does look like it could be jugate busts rather than a double-struck obverse. Does anyone know if this reverse was paired with a jugate bust?
I'm seeing maybe a bit of a double strike, but not a jugate portrait. This reverse type was not issued in jugate and if it was, the obverse legend would reflect the two Emperors. Compare with the jugate below from Trier off AC search.
Not double struck or a double portrait. Encrustation on cheek and a flan void at the forehead create the optical illusion that there are two busts. Barry Murphy
