| AE | Base metal, or base metal alloy, such as copper, brass or bronze |
| AR | Silver |
| AU or AV | Gold |
| Billon | Debased silver; An alloy of silver mixed with a base metal (bronze or copper) where the base metal makes up more than 50% of the alloy |
| Brockage | A brockage is mistruck coin where one side is normal and the other is an incuse reversed version of the normal side. They occured when a coin stuck to the die after striking, and wasn’t removed before striking the next coin (the brockage coin). The stuck coin became a new die until it was removed. You can see some examples here |
| Centered/Centering | How well the flan is aligned with the dies before striking. Because the flan and the dies were not mechanically held together during the striking process, they could be laterally offset from each other. A well centered coin will have all of the design centered on the flan. A badly centered coin may only show half of the design, with the other half of the coin left blank |
| Devices | The features on the coin. Basically, the bits of the design that aren’t fields |
| Die | A piece of hardened metal (bronze or iron) used to impress the design into a flan. Each side of a coin needed its own die. There were three ways to get an image onto the die:- Engraving
- Hubbing (see below)
- Casting. The dies had to be cast anyway to form the shape, so it was feasible to cast the design at the same time
Regardless of which method was used to get the image onto the die, someone had to engrave something. It is thought that engraving the die directly was the most common method used |
| Die Breaks | Repeated hits with a hammer caused the dies to break. These generally started small, but would grow as the die kept being used. You can trace how they progressed by looking at different coins minted with the same die. A die break is usually a piece of metal breaking off of the edge of a device or the edge of the die, but could form anywhere. Die breaks will leave a raised area on the struck coin. |
| Die Wear | Repeated hits with a hammer caused the dies to wear. The devices (raised areas on the coins) were sunk into the die creating an incuse image. As the die was used, these wore away and became wider. Coins struck with these dies had wider devices, and this could eventually cause devices to merge and small detail to be lost |
| Double struck | A double (or more) struck coin occured when multiple strikes were used, and the flan moved between strikes. This caused the image to appear multiple times on the coin. See “Overstruck/Understruck/Undertype” |
| Field | The blank and flat areas on either side of a coin; the parts of a coin’s surface not used for the design or the text |
| Flan | The blank disk which is struck to produce a coin |
| Flan Defects | A flan defect is a problem with the flan itself. They can be caused during the flan moulding process, or during striking. Defects caused during the moulding process were likely to be voids. The striking process could cause the flan to crack, chip, split (a v-shaped hole at the edge) or even change shape. Lamination, where a bad alloy mix caused part of the surface to flake away, could happen before or after minting. Flan defects are a great way of detecting fake coins. No two coins should ever have the same defects |
| Flow Lines | These are lines radiating out from the center of the coin. As the flan was struck, the metal in the flan deformed under pressure and flowed into the holes in the die, which is what created the devices (the raised areas on the coin). Some flow lines appear below the surface of the coin, and these are unique to each coin. Others sit above the surface of the coin, and are caused by the die. The flowing metal would eventually mark the die, and these marks would start to appear as raised lines on subsequent coins. |
| Fourre | A coin with a core made of a lesser metal, and plated in a precious metal. For example, a bronze core coated in gold. While most fourres were made by counterfeiters, some may have been official issues intended to decieve:analysis has shown that such forgeries were being produced in official Macedonian mints specifically for trade with the ‘barbarians’, i.e. there existed an official policy on behalf of the Macedonian authorities to systematically defraud their trading partners
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| Grade | A subjective rating used to describe the condition of a coin. Machine made modern coins are all identical, differing only in the amount of circulation wear they have. This can be described by a single value. Ancient coins, on the other hand, became unique the moment they were struck, varying by the artistic quality of the die, the wear on the die, the strength of the strike, the centring of the flan between the dies, the shape of the flan, and cracks and other deformities that formed when the flan was struck. A grading system has to take all of this into account, as well as circulation wear, what happened to it when it was in the ground for a couple of millennia, and the fact that the obverse and reverse dies could vary independently, so you could have an excellent, mint-state, reverse, and a worn and flawed obverse. This makes ancient coins much harder to grade than machine made modern coins. Representing all of that variability with just one grade is very subjective, and without seeing a photo of the coin, you can’t really guess what you’re getting. Of course, if you have a photo (and almost all coins are bought today after seeing good quality photos), then the grade isn’t that important. It’s possible to grade each of these aspects individually, but most ancient-coin collectors don’t bother. Instead, they use an unquantifiable metric called “eye appeal” which basically boils down to a two grade system – “Coins I like” and “Coins I don’t like” |
| Hubbing | Hubbing is the process of creating a new die from a positive stamp rather than cutting it by hand. The “positive stamp” could be a real coin, or a special die that looked like a coin (called a matrix). The die would have been heated to make it soft, and then the coin or matrix would have been hammered into it to transfer the image Hubbing was done to either save time or to create forgeries. Dies hubbed from coins can be detected because the full design won’t transfer unless the coin was perfectly centered. When new coins are made from this die, the design will stop a distance from the edge because that part of the design wasn’t present on the original coin |
| Legend | The words engraved around the outside of the obverse and/or reverse |
| Numismatics | The study of coins |
| Numismatist | Someone who studies coins |
| Obverse | The “head” side of the coin which shows the portrait. However, many ancient coins either had no portraits on them, or they had one on each side, so techically, the obverse is the side that was face down when the coin was struck. As the obverse die wasn’t constantly being hit with a hammer, it lasted longer, so the more important design was put on this side |
| Test cuts | A test cut is where someone in antiquity cut the coin open to check that the coin was made from the same metal all the way through. It was used to detect counterfeits which were made from copper, bronze or lead, and just plated with gold or silver |
| Overstruck/Understruck/Undertype | An overstruck coin is one that has been struck more than once and shows multiple designs. When this occured because the die moved during striking, we tend to say it was double struck (see above). Overstruck is generally used for the case where a a pre-existing coin was used as the flan. This was an easy way to make sure the value of the new coin matched an existing coin, and it also cut out the flan preparation time. Coins minted this way are called overstruck coins. The coin that was used as the flan is called the undertype. The overstrike is the image that appears on top (the last one formed), and the understrike is all the other images that appear. For example, if a coin was struck three times and the die moved each time, the last image laid down is the overstrike, and the first two images laid down are the understrikes |
| Patina | A layer of oxidized metal that can coat bronze and copper coins. Patina can form in many colours, but green is the most common. A good patina can increase the value of a coin |
| Planchet | See Flan |
| Provenance | The history of ownership of the coin. A complete provenance records where and how the coin was found, and every sale and owner since that point. The provenance can increase the value of a coin if it has been in famous collections, or passed through the hands of respected dealer |
| Reverse | The “tail” side of the coin. The reverse is the side that was face up when the coin was struck. The reverse die was the one hit with the hammer |
| Slug | A coin that’s so worn that there’s almost no detail left |
| Strike | The process of imprinting the design onto the flan by striking the reverse die with a hammer. Strike is also used by some as an attribute in grading ancient coins, and it accounts for all factors that were in effect at the moment of striking such as centering, strength of strike, evenness of strike (were the dies parallel), die state, etc. |
