Coins have been counterfeited since the invention of coinage.
Before coinage, pre-coin precious metal ingots were counterfeited as well. In ancient times, forgers typically
counterfeited coins by plating a base metal core with a precious metal exterior, since the value of coins was tied
to the value of their metallic content. Such coins are called fourrees.
The word "fourree" is seen with alternate spellings, including the French "fourrée,"
"fouree," "fourre," and "foure," with the term derived from the French word for "filled."
Less frequently the Latin term "subaeratus," meaning "bronze beneath," is used (the Greek equivalent
Fourrees are believed to have been made using a number of different techniques. With silver coins, the most common
method is thought to have involved wrapping silver foil around base-metal planchet, heating it, and striking the
coin. In some or perhaps many cases, liquid or powdered solder may have been used to help fuse the foil to the
planchet. In other cases, a thinner coating of silver is thought to have been produced by dipping a base-metal
planchet in a silver solution. With gold coins, gold foil or thinner layers of gold leaf are thought to have been
wrapped around the planchet and then burnished down before striking. The foil or leaf may have been affixed to
the planchet by heating or with an adhesive such as gum arabic. In other cases, the planchet may have been coated
with a liquid gold/mercury amalgam then heated to dissipate the mercury.
With both silver- and gold-plated coins, the plating was typically applied to the planchet before the coin was
struck to prevent the softening or blurring of the design details, as happens today when current coins are electroplated.
Fourrees are usually lighter than official coins, with the interior of gold fourrees typically consisting of silver
or copper, which are both lighter than gold, and with the interior of silver fourrees typically consisting of copper,
which is lighter than silver. Counterfeiters used other metals too, including lead and iron, with some rare fourrees
of bronze coins extant that were made from bronze-plated iron. With silver and gold fourrees the weight can be
in the correct range if lead was used in the interior or if the flan was made larger than normal. Specific gravity
testing can be helpful in the case of overlarge flans. It's likely that some percentage of fourrees with lead interiors
have not yet been detected. Some fourrees are found with all of the interior base metal, probably iron, having
corroded away, leaving just the silver plating as an empty shell that filled in, underground, with dirt, sand,
One way to check if an ancient silver coin is a fourree is simply to feel it. Because silver is a much better heat
conductor than copper, pure silver coins will feel cooler to the touch than silver-plated copper or lead coins.
The silver coin will be more effective in drawing heat away from your skin. You should test a questionable coin
against a known good coin of the same type and the same denomination.
Another method is to look for edge cracks. If you find one, poke a straight pin into it and scratch away a tiny
amount of metal. If the underlying metal inside the crack is yellow or orange, that indicates a gold or bronze
core. If the metal is gray but soft, that indicates a lead core. If the metal is gray but hard, that indicates
a silver core. The pin prick, inside the edge crack, won't be visible unless you look inside the crack.
With many fourrees breaks appear in the plating, revealing the interior metal. The breaks may have been caused
in part by the wearing away of the highpoints of the coin's design through circulation, but most appear to have
been caused primarily through corrosion from the coin having been buried in the ground for two millennia. This
allowed gases and liquids to enter underneath the plating, causing a bubble or blister and then a break in the
plating at that spot.
Some of the breaks in silver fourrees show three different layers, a silver one consisting of the silver plating,
an orange one consisting of the copper core, and a green one separating the silver plating from the copper core.
This green layer is sometimes called the "eutectic" layer and according to metallurgical tests consists
of 72 percent silver and 28 percent copper. It's unclear whether the eutectic layer was a copper-silver solder
applied to help bond the silver plating to the copper core or was formed when the silver-plated planchet was heated,
partially melting and interdiffusing the silver and copper.
Fourrees are debased coins, but not all debased coins are fourrees. Some later official Greek silver coins and many official Roman
silver coins were progressively debased, with increasing amounts of copper deliberately mixed into the silver/copper alloy. Severely debased, "surface-enriched" Roman coins were made through
creating a planchet of copper alloyed with a small amount of silver, then pickling it with an acid before striking.
The acid leached copper from the surface and left a thin layer of nearly pure silvering, though the silvering frequently
wore away as the coin circulated or corroded away as it lay underground for many centuries. Later Roman coins may have been "silver washed," with the planchets being covered with a very thin silver-mercury amalgam.
Sometimes Roman surfaced-enriched or silver-washed coins are described as being made of billon, which technically is an alloy of silver with a higher proportion of base metal. But these coins are almost entirely base metal, and most people today refer to them as bronzes. It's not clear if Rome was able to fool anybody in ancient times with these base metal coins that affected the appearance of precious metal coins or even if that was its intention.
Just as not all debased coins are fourrees, not all ancient counterfeits are fourrees. Some no doubt were made with a homogeneously debased alloy, and it's likely that some percentage of these are as yet undiscovered. More widespread use of nondestructive metallurgical testing would reveal more insights on this. Some homogeneously debased ancient coins are official coins made by tribal peoples in imitation of the official Greek or Roman coins they came in contact with.
Though most fourrees are considered ancient counterfeits, not all are. The most notable exception is Emergency Issue Owl fourrees, which were officially issued by Athens at the end of the Peloponnesian War when Athens was low on silver reserves and desperately needed money to try to avoid the eventual defeat by the Spartans. It's not clear if these coins were made to deceive others or if they were fiduciary, with Athens backing them with promises of future payments in silver, asking its citizens, and perhaps its allies as well, to help out during this time of crisis. No ancient documentation exists that addresses this. What is clear is that there are many other instances throughout history of the use emergency money, also known as siege pieces, provisional money, and necessity money.
Another area of debate is whether other ancient coin series
were officially minted as fourrees using government facilities. During Roman times in particular, traveling military
mints may have issued plated coins.
Still another area of debate, with fourrees, is whether those doing the counterfeiting were always independent
or whether in some cases they were official mint workers trying to make extra money on the sly using stolen or
borrowed dies. The latter seems a likely enough scenario, but no definitive die links have thus far been found
indicating that official dies were used for both good-metal coins and fourrees. What have been found are die links
indicating that forgers in at least some cases used an official coin to make transfer dies that were then used
to strike fourrees (Crawford, Roman Republican Coinage, 1974, p. 561, no. 8, pl. LXV, no's 1-2.).
Some modern official coins are plated, such as the current U.S. cent, issued in its present form since 1982. It
consists of copper-plated zinc (the plating is 100 percent copper while the interior is 99.2 percent zinc and 0.8
percent copper). But it and other plated modern coins are never referred to as fourrees. Modern clad coins, including
current U.S. dimes and quarters, aren't regarded as being plated since their edges reveal their interior.
In ancient times, punishment for making counterfeit money could be death, a punishment that has existed at various
times and in various places since then as well. Despite this, there are many surviving fourree counterfeits of
ancient coins, indicating a sizeable presence in ancient marketplaces.
The existence of fourrees in ancient times is the reason that some ancient coins were test cut, which involved
the slashing of the surface of a coin with a hammer and chisel to reveal the interior metal, or punchmarked, which
involved punching a design or banker's mark into the surface (punchmarking was sometimes done instead to retariff
a coin at its place of origin or certify it as legal tender beyond its place of origin). To try to prevent detection,
some counterfeiters made fourrees with test cuts engraved into their design, though these are seen rarely today.
In ancient times some test-cut coins were consequently further test cut within the existing test cut. Naturally,
counterfeiters then made some fourrees engraved with test cuts within test cuts, though these are even rarer today.
Fourrees are typically unearthed as individual finds rather than as part of hoards, sometimes with test cuts on
them, usually without. This indicates they didn't fool anybody long enough to be regarded as worth saving. Many
were likely destroyed. The percentage of fourrees compared with good-metal coins on the market today is likely
considerably less than the percentage in ancient times.
Fourrees are considered collectable by many, though most collectors regard them as less desirable than official
coins, so despite the fact that they're seen far less than official ancient coins they sell for about 25 to 40
percent of what the same official ancient coin would sell for. Unusual mule fourrees that combine an obverse and
reverse from different coins, on the other hand, can sell for more that the equivalent official coins. Convincing
modern forgeries of ancient foil-type fourrees may well exist, though they would take more effort to produce, would
lead to relatively little material savings, and would bring less on the market than good-metal forgeries. Modern
fakes exist that consist of silver electroplated over base metal, but they're typically unconvincing tourist copies
and they copy good-metal official ancient coins rather than fourrees.
Here are some pages illustrating specific ancient fourree counterfeits.