The lettering looks "off" to me. I could very well be wrong, but based on the one picture, I would avoid it.
Look at the small irregularities in the field, particularly above and behind Hadrian’s head, and also how the devices meet the fields.
It looks "funny" to me too, both for stylistic reasons and surfaces, but I could be wrong. If it helps, I have a "real fake" Hadrian sestertius made out of base metal. I think mine is a soapy cast of an original, so the style is okay:
Hmm the roughness at the back of Hadrian's head looks bad, but then again to me the brown deposits to the right of Hadrian's head look convincing. If it's a cast fake then it seems to be an old fake. Usually forgers make casts of genuine coins, so it will be quite unusual for the style to be wrong on a cast fake. I really don't see anything wrong with this coin's style. Take a look at this example for a style comparison: https://www.acsearch.info/search.html?id=3173029
I don't arrogate to be able to give any qualified assessment of this coin. Also, even true experts cannot determine the authenticity of a coin based on images alone. There is a reason why authentication services such as David Sear's have you send in the coin itself and not only pictures. That said, there are a couple of things about your Hadrian that strike me as odd, and I will explain them below. Let's start by comparing your coin to an authentic Hadrian as with a very similar obverse from my collection: 1.) You will immediately notice that the coin on the right appears to be much better preserved, or, in a terminology I don't particularly like, "in higher grade." Allmost all details and letters are fully visible, there appears to be only little wear, the surfaces are even and smooth. This obviously doesn't make it a fake, but it justifies to ask: do we see (a) an exceptionally good coin, (b) a modern forgery, or (c) a tooled coin? 2.) Looking closely at the details on hair, ear, and laurel wreath, it seems that the lines on the right coin are both stronger and a bit more coarse than on the left coin. It also appears that the right coin is a bit flatter. Notice that although there is ample hair detail, Hadrian's beard is quite worn. All of this makes me suspect that your coin saw considerable wear and at some point looked similar to mine. Someone might have tried to "enhance" it by reengraving ("tooling") the lost details. In hand, an expert should be able to confirm or confute this suspicion. 3.) Let's talk about patina and surfaces. The coin on the left has a natural, slightly uneven malachite patina with all sorts of regular imperfections. Your coin, on the other hand, appears to have very smooth and even surfaces, a brown patina with some reddish spots, and some grey deposits. Notice that the red spots don't protrude, as they often do. The brown on your coin looks like the color you get when treating copper with liver of sulfur and ammonia or similar substances. I would bet a fine Rebublican denarius that the "sand patina" deposits have been artificially applied to highlight details – a deplorable but common practice with some dealers. This would also explain the roughness behind the head Nicholas Molinari and others noted: here, not that much smoothing took place and some of the "make-up" got caught in the remaining roughness. Hence, if you asked me for a guess, which is categorically different from an opinion or even verdict, I'd answer that maybe your coin has been at least partially depatinated, smoothed, tooled, chemically repatinated, and treated to some artificial dust in order to hide these alterations? If you seriously consider buying this coin or just want to know for sure, you probably should show it in hand to an experienced and trustworthy dealer or comparable expert. I would refrain from buying coins in this grade from sources that don't have guarantees of authenticity and a reputation of making inevitable mistakes good.
If @Ken Dorney and others think it is cast, then, by all means, trust their judgement. It most likely is!
Isn't patination on roman bronzes usually a bit more even? You can see some of the orange on the surface as well as the lettering. Also, how round is too round for a sestertius?
They can be pretty round: RIC Vol. I, CAIUS (CALIGULA), SESTERTIUS, Rome, No. 51, 40-41AD, (35mm, 26.2gm) Obverse depiction: Personification of Pietas, seated left Obverse Inscription: C CAESAR DIVI AVG PRON AVG PM TRP IIII PP In exergue: PIETAS Reverse depiction: Caligula standing left holding patera over altar - attendants (victimarius) on either side holding bull for sacrifice - hexastyle temple of Divus Augustus festooned with garlands in background. Reverse Horizontal Inscription: {small lettering} DIVO AVG and below: S C (left and right) RIC Vol. I, NERO, SESTERTIUS, Rome, No. 356, 66-67AD, (36mm, 24.8gm) BMCRE Vol. I, NERO, SESTERTIUS, Rome, No. 114, 66-67AD, Obverse depiction: Nero, laureate head facing right Inscription: IMP NERO CLAVD CAESAR AVG GERM PM TRP XIII PP Reverse depiction: Personification of Roma seated left on cuirass resting elbow on shield and holding spear, helmet behind Inscription: ROMA in exergue S C left and right RIC Vol. I, CLAUDIUS, SESTERTIUS, Rome, No. 112, 50-54AD (36mm, 28.2gm) Obverse depiction: Claudius, laureate head facing right Inscription: TI CLAVDIVS CAESAR AVG PM TRP IMP PP Reverse depiction: Civic Oak Wreath Inscription in four lines: EX SC P P OB CIVES SERVATOS (within Civic wreath)
True, true. I just meant that the edge of the coin look a bit artificially "sharp". But I guess you're right.
