This Roman base metal coin was sent in by Mike Ruszynski, who wanted a full ID and some idea of its possible value. It is shown greatly enlarged but is actually 26mm in diameter.
Mike’s find is a billon follis of Maximinus II, which was struck when he was Caesar under Galerius Maximian (AD 303-10). On the obverse the legend reads GAL VAL MAXIMINVS NOB C around the laureate, draped and cuirassed but of Maximinus. On the reverse is the standing figure of Genius, who holds and patera and a cornucopia, and the legend reads GENIO POP ROM. Directly below Genius are the mint letters for London (PLN). This type of follis was issued in AD 307 and in volume IV of Roman Coins and Their Values it is listed as number 14732.
The coin has some weak areas, in particular on the high points but is otherwise a decent specimen. Being from the mint situated in London this would make it more interesting for some collectors. In its present state of preservation I would price it at £25.