Here is what I think is an interesting coin. The obverse is Constantine II paired with a reverse meant for Constantine I (similar to Aquileia 65). Anyway, I think that it is from Aquileia, as the mintmark looks like AQ?. RIC does not list this bust type (K2) during this period from Aquileia though; so perhaps it is from another mint; but the mintmark looks like Aquileia. I don’t have any measurements for the coin.
Constantine II
Circa A.D. 320- 321
CONSTANTINVS IVN NOB C; laureate and wearing Imperial robes, holding eagle-tipped scepter.
DN CONSTANTINI MAX AVG surrounding laurel wreath enclosing VOT/XX.
In ex. AQ?
The bust type is also unusual for the type and for Aquileia as a mint.