Weighing just 9.53 g. the following coin has deified Empress Faustina on obverse. Reverse shows Ceres standing and holding a torch and corn ears. The nearest attribution is Cohen 80. Is it an As or a Dupondius ? How can we make sure about these denominations, once for all.
You can remove the patina If you don't want to do this, an elemental analysis on zinc might give a result.
Seriously.. Can we methodically identify the denominations of Roman bronze coins, aside from usual dimension ?
That coin is RIC 1169a; BMCRE 1566; Cohen 80; Strack 1286; RCV 4645. Here is my example: Faustina I, AD 138-140. Roman Æ as or dupondius, 12.09 g, 25.7 mm, 7 h. Rome, AD 150 or later. Obv: DIVA FAVSTINA, bare-headed and draped bust, right Rev: AVGV STA SC, Ceres standing left, holding corn ears and long torch Refs: RIC 1169a; BMCRE 1566; Cohen 80; RCV 4645. With middle bronzes of the Antonine women, the only way to definitively distinguish between the dupondius and the as is if the bare metal shows through the patina, the dupondii being a brassy yellow and the as being a coppery red. The weight can offer a cue. The British Museum specimen, identified as an as in BMCRE4, p. 250, weighs 8.82 g. Of the three asses in OCRE, two of them weigh less than 10 g, while the third weighs 11.62 g. OCRE references three dupondii, ranging in weight from 10.047 g to 14.180 g. You can see there is overlap between them, but coins less than 10 g are very likely asses, while coins more than 12 g are very likely dupondii. Fabric can help distinguish them as well; asses tend to be struck on thinner, more raggedy flans than their thicker, smooth-edged dupondii counterparts. On the basis of these features, I believe my coin is a dupondius, but I don't know for sure.
