Reverse could be that of the
CONSECRATIO As of
Diva Faustina I, as picture below.
Obv. could be
Marcus Aurelius as
Caesar towards the end of the reign of A. Pius, probably what R. Smits was thinking of. See the
sestertius below; similar
portraits also appear on
his middle bronzes.
22 mm is small for a middle bronze; we expect 25-6 mm.
If official, your coin could be an interesting
mule, suggesting an exact date of late in Pius' reign for Faustina's
CONSECRATIO As. If it's an ancient imitation, however, then it's just a counterfeit's random combination of dies based on prototypes of what could be quite different periods, so does not
help with the chronology of the official coinage.