While searching at Wildwinds site I noticed that a coin I've always neglected could be rare,silver and belonging to a late known hoard of the nineteenth century. It's an Antoninianus of Emperor Gallienus that weighs 3.74 g. The coin is listed as RIC 445 from Antioch. In case it's silver, it would be from the Cunetio Hoard of 1879 and considered as rare- Gobl 1698 m. Otherwise, it would still be RIC 445 but lsted also as Sear 5-10298, or even RSC 705 a. The coin is much better at hand than scanned. Please try to animate this complicated research. The reverse shows goddess of the East ORIENS turreted and delivering a wreath to the Emperor.
I highly doubt the Cunetio Hoard would be the only coins physically silver, and all others billon. My guess is the hoard was accidentally called silver when in fact all Gallienus coins should properly be called billon in my experience. Other than that I do not have any specific knowledge on this coin.
