Mislabeled Roman coin?
This coin came labeled as an Antoninianus from Diocletian, but I have some doubts.
Obverse: (?)IENVS AVG
Reverse: DIA(?) (?)S AVG
At the bottom of the reverse, XI is readable.
Any ideas if it might be a different coin? Also, should the coin be cleaned or left as is? Is the green patina or damage? Thanks!
Hi Ludwig --
Some searching in my database produced this Antoninianus coin with stag. Here's the auction description from 2010:
Classical Numismatic Group > Electronic Auction 225
Lot number: 440
Price realized: 145 USD (Approx. 100 EUR / 89 GBP / 148 CHF)
Roman Imperial Coinage from the White Mountain Collection
Gallienus. AD 253-268. AR Antoninianus (19mm, 2.47 g, 5h). Rome mint, 10th officina. 10th emission, AD 267-268. GALLIEN VS AVG, radiate head right / DIANAE C[O] NS AVG, stag advancing right; X. RIC V 179; MIR 36, 745t; RSC 157. Good VF, brown surfaces, small flan crack. Exceptional for issue.
As far as I know, the green discoloration is called verdigris. Wikipedia: Verdigris is the common name for a green pigment obtained through the application of acetic acid to copper plates or the natural patina formed when copper, brass or bronze is weathered and exposed to air or seawater over time. It is usually a basic copper carbonate, but near the sea is a basic copper chloride.
I have heard -- but I have never tried it -- that verdigris can be removed by soaking the coin in olive oil for a long time.