Anyone care to venture a guess as to what the bumps are on this Hadrian sestertius? HADRIAN (117-138). Sestertius. Rome. Obv: HADRIANVS AVGVSTVS. Laureate bust right, with slight drapery. Rev: P M TR P COS III / VIRT - AVG / S - C. Virtus standing left, with foot set upon helmet, holding parazonium and spear. Cf. RIC 696 (without drapery). Condition: Near very fine. Weight: 26.17 g. Diameter: 33 mm.
I don't know. The details look quite sharp. I'd guess some local chemical reactions under the patina. You sometimes see this on sestertii.
Coin zits. But seriously, its a type of corrosion which ultimately leads to pitting. They may or may not be stable, impossible to say, but if you do buy it handle it carefully so that they dont 'pop' and leave a pit. If you look closely at the photo you will see pits where these zits have indeed popped.
I have a Sabina sestertius with similar bits of corrosion, particularly on the reverse: Sabina, AD 117-137. Roman orichalcum sestertius, 22.51 g, 31.2 mm, 6 h. Rome, AD 132. Obv: SABINA AVGVSTA HADRIANI AVG P P, diademed and draped bust, right. Rev: IVNONI REGINAE, Juno standing left, holding patera and scepter. Refs: RIC 1028; BMCRE 1869; Cohen 38; RCV 3934; UCR 500; Strack 864.
Yup. Corrosion. Apparently the different metals were not evenly distributed in the bronze-smelting process and left pockets of unstable impurities. I don't think the process is likely to get any worse, though. That is, as long as you're not a compulsive scab-picker.
