How to Tell If a Roman Coin Is Real: 9 Checks You Can Do at Home
Short answer: weigh it, measure it, put a magnet near it and look hard at the edge. A coin whose weight and diameter fall inside the published range for its denomination, that ignores a magnet, that has no continuous edge seam, and whose surfaces show sharp struck detail rather than soft cast detail, is very probably genuine. The great majority of fakes fail at least one of the first four checks.
Roman coins were struck by hand between engraved dies, one at a time, in their tens of millions (Burnett, 1987). That production method leaves physical evidence a modern copy struggles to imitate, and it is evidence you can read at a kitchen table with a set of digital scales and a magnifier. What follows is the order a specialist works in, from the cheapest checks to the ones that need experience.
What you need
- Digital scales reading to 0.01 g — the single most useful tool you can buy
- Digital callipers, or a millimetre rule at a pinch
- A 10x loupe or a phone macro lens
- Any small magnet
1. Weigh the coin and measure the diameter
Roman mints worked to a target weight expressed as a fraction of the Roman pound, and although individual flans vary — they were cut and adjusted by hand — they cluster tightly around that target. A coin sitting well outside the band for its denomination and period needs an explanation.
| Denomination | Metal | Typical weight | Typical diameter |
|---|---|---|---|
| Aureus (Augustus–Nero) | Gold | 7.2–7.9 g | 18–20 mm |
| Denarius (1st century AD) | Silver | 3.1–3.9 g | 17–20 mm |
| Denarius (Severan, c. AD 200) | Debased silver | 2.6–3.6 g | 17–20 mm |
| Antoninianus (mid 3rd century) | Billon / silvered | 2.2–4.5 g | 20–24 mm |
| Sestertius | Orichalcum | 21–28 g | 32–35 mm |
| Dupondius | Orichalcum | 11–14 g | 26–29 mm |
| As | Copper | 9–12 g | 25–28 mm |
| Follis (after AD 294) | Silvered bronze | 8–11 g | 26–30 mm |
| AE3 (mid 4th century) | Bronze | 1.5–3.0 g | 15–19 mm |
| Solidus (after AD 309) | Gold | 4.3–4.6 g | 19–21 mm |
Two failure patterns matter. A coin that is light for its type is often a plated ancient counterfeit or a modern cast in a low-density alloy. A coin that is heavy and slightly too thick is a common signature of casts made from a mould taken off a real coin, because the copy reproduces the design but not the original density.
2. Try a magnet
This takes two seconds and eliminates a whole category of tourist replicas. Gold, silver, copper, brass and bronze are all non-ferrous. Nothing the Romans struck responds to a magnet. Any attraction beyond the faintest tug from soil residue means iron or steel in the alloy, which means modern.
3. Look for a casting seam
Turn the coin on its edge under good light and rotate it slowly. Modern fakes are overwhelmingly cast, usually in a two-part mould, and the join leaves a raised ridge running the full circumference exactly halfway up the edge. Forgers file it off, which replaces one problem with another: a flat, uniformly filed edge on a Roman coin is itself wrong.
Genuine struck flans have irregular edges. You may see hammer marks, small radial flan cracks where the hot metal split under the die, casting sprue marks from flan manufacture on some bronzes, and an edge that is subtly thicker on one side than the other. Irregularity is a good sign.
4. Read the surface: bubbles versus porosity
Under a loupe, a cast fake shows small round pits with soft, rounded rims — trapped air bubbles. The whole surface tends to look slightly granular and sugary, and details fade into the field rather than rising from it.
A genuine struck coin that has been buried shows a different texture: irregular, angular corrosion pitting that follows the crystal structure of the metal (Scott, 2002), often concentrated where the metal was thinnest. Crucially, on a struck coin the fine details stay crisp where the surface survives. Cast fakes lose detail evenly across the whole coin.
5. Check for evidence of striking
Striking pushes metal outwards from the centre of the die. On genuine coins this leaves signs a mould cannot copy:
- Flat spots. Hand striking rarely fills the die completely, so part of the legend or the high point of the portrait is often weak while the rest is sharp.
- Off-centre designs. The flan was placed by hand. Perfectly centred coins exist but are the exception, especially in the 3rd and 4th centuries.
- Die cracks. Raised, irregular lines crossing the field where the die itself had failed. A raised line is a die crack; a sunken line is damage.
- Double strikes. Ghost outlines where the flan shifted between blows.
These faults are positive evidence. A Roman coin with none of them and machine-perfect symmetry deserves more scrutiny, not less.
6. Judge the style
This is where experience starts to matter, and it is also the check that catches good fakes. Roman die engravers worked within tight conventions that changed by reign and by mint (Kent, 1978). Modern forgers copy the design but reproduce it in a modern hand.
Look at the letters first. Roman lettering has consistent serif treatment, consistent stroke weight and consistent spacing relative to the flan. Fakes commonly show letters that are too even, too rounded, or spaced as if set by a typographer rather than punched by hand. Then look at the portrait: hair rendered as generic texture rather than as distinct locks, an eye drawn rather than modelled, or a neck truncation that does not match the period, are all warning signs.
The way to build this eye is to look at several hundred genuine examples of the same type in an auction archive before you buy one.
7. Check the die axis
Hold the coin by its edge with the obverse upright, then flip it vertically. The angle at which the reverse sits is the die axis, expressed as a clock position or in degrees. Different mints and periods favoured different axes (Casey, 1986) — much early imperial material is variable, while many later issues cluster at 6 or 12 o'clock. On its own this proves nothing, but a die axis that contradicts the norm for a well-documented issue is one more thing that needs explaining.
8. Match the type against a published reference
Every legitimate Roman coin type is catalogued. If the exact combination of obverse legend, portrait, reverse type and reverse legend on your coin does not appear anywhere in the standard references, the likeliest explanation is that a forger invented it.
- RIC — Roman Imperial Coinage, the standard reference for the imperial series (Mattingly et al., 1923–1994).
- RRC — Crawford's Roman Republican Coinage for the Republic (Crawford, 1974).
- RPC — Roman Provincial Coinage for civic and provincial issues (Burnett, Amandry and Ripollès, 1992).
- OCRE — Online Coins of the Roman Empire, a free searchable index tied to RIC (American Numismatic Society, no date).
- Auction archives — searching sold results by emperor and reverse type shows you dozens of genuine examples of the same dies.
Auction archives serve a second purpose. Prolific forgeries circulate in quantity, so if you find your exact coin appearing repeatedly in identical condition from multiple sellers, you are almost certainly looking at one mould's output.
9. Be suspicious of perfection
The commonest way collectors lose money is not on crude fakes but on coins that look too good. A sharply detailed, fully centred, evenly patinated coin of a famous emperor offered well below the going rate is the classic profile of a modern struck forgery. Genuine coins in that condition are expensive precisely because they are rare, and they are sold by people who know exactly what they have.
What these checks will not catch
Three problems survive every test above and need a specialist:
- Transfer-die forgeries. Dies made directly from a genuine coin, then used to strike new flans of correct weight and alloy. The style is right because it is the original style. These are identified by comparing the coin against known genuine examples and looking for shared, repeated flaws.
- Tooling. A genuine but worn coin re-engraved with modern tools (Casey, 1986) to sharpen hair, letters or drapery. Under raking light the recut areas show a different surface character from the untouched fields.
- Smoothing. Corrosion products carefully removed from a bronze to leave a falsely clean field. Common, widely disclosed by good dealers, and materially value-reducing when it is not.
None of that should discourage you. The checks on this page filter out the overwhelming majority of what is offered to new collectors, and the residue is exactly what a written authenticity guarantee from a reputable seller exists to cover.
Frequently asked questions
Are Roman coins magnetic?
No. Genuine Roman coins were struck in gold, silver, orichalcum (a brass alloy), copper or leaded bronze, none of which are attracted to a magnet. If a coin sold to you as Roman jumps to a magnet, it contains iron or steel and is a modern replica. A weak, non-jumping attraction is usually iron in the surrounding soil deposits rather than the coin itself.
Does a seam around the edge always mean a fake?
A fine raised line running the whole way round the edge is the tell-tale mark of a two-part casting mould, and Roman coins were struck between dies, not cast. Genuine coins can show irregular edge splits, flan cracks and file marks from flan preparation, but those are uneven and localised. A continuous, perfectly centred seam means a modern cast copy.
What is a fourree, and is it a fake?
A fourree is a base-metal core wrapped in a thin silver foil, struck from official-looking dies. They are ancient counterfeits, made in antiquity, and they are collected in their own right as evidence of Roman monetary crime (Grierson, 1975). They are worth far less than a solid silver denarius but they are genuine ancient objects, not modern forgeries. Look for a low weight, a copper-coloured break in the plating, and blistering where the foil has lifted.
Can a coin be genuine but still worthless?
Yes, in two ways. Extremely worn late Roman bronzes are authentic but often trade for very little. More importantly, a genuine coin whose surfaces have been tooled, smoothed or re-engraved by a modern hand loses most of its market value even though the flan itself is ancient. Tooling is the hardest problem in ancient numismatics and the main reason serious buyers pay for expert opinion.
References
- American Numismatic Society (no date) Online Coins of the Roman Empire (OCRE). Available at: http://numismatics.org/ocre/ (Accessed: 26 August 2026).
- Burnett, A. (1987) Coinage in the Roman World. London: Seaby.
- Burnett, A., Amandry, M. and Ripollès, P.P. (1992–) Roman Provincial Coinage. London: British Museum Press / Paris: Bibliothèque nationale de France.
- Casey, P.J. (1986) Understanding Ancient Coins: An Introduction for Archaeologists and Historians. London: Batsford.
- Crawford, M.H. (1974) Roman Republican Coinage. Cambridge: Cambridge University Press.
- Grierson, P. (1975) Numismatics. Oxford: Oxford University Press.
- Kent, J.P.C. (1978) Roman Coins. London: Thames and Hudson.
- Mattingly, H., Sydenham, E.A., Sutherland, C.H.V. and Carson, R.A.G. (eds.) (1923–1994) The Roman Imperial Coinage. 10 vols. London: Spink.
- Scott, D.A. (2002) Copper and Bronze in Art: Corrosion, Colorants, Conservation. Los Angeles: Getty Conservation Institute.
- Sear, D.R. (2000) Roman Coins and Their Values, Volume I: The Republic and the Twelve Caesars, 280 BC–AD 96. London: Spink.
Referencing follows the Harvard (author–date) system. Where figures are given as approximate ranges, they are drawn from the works above; published analyses differ by mint, issue and method, and market figures reflect prices observed at the date of writing.