Precious metal coins have long been appreciated, both for their historical and monetary value. Since their conception thousands of years ago, coins have held a special place in the human psyche and have since become items highly sought after. In the case of rare, antique and valuable coins, the worth of these coins has been widely collected and studied within the field of numismatics. This area of study tracks the historical production of coins and both their cultural significance and impact.
With the large collection of coins that have been produced by human beings, there have been challenges raised for both numismatists and coin collector hobbyists. Counterfeit U.S. coins—fake coins—have been in circulation throughout the Americas ever since their creation. The issues that arise with fake coins being rife and intermixed within monetary circulation is that people, especially collectors, need to be aware of when a counterfeit might be on their hands.
For those of you buying coins either for their historical, numismatic value or for their value in precious metal, you should know the basics of how to catch a counterfeit before being duped. Below, we’re going to explore some of the basic types of counterfeit U.S. coins you’ll find strewn throughout the market, and what tests you can implement to catch one along the way.
The Types of Fake Coins
Counterfeit coins come in a variety of different forms, most of which are created either to (1) recreate a precious coin that is normally minted by a country or region or (2) modifying a regular coin to make it look more expensive—to harbor more numismatic value—than it actually is. Fake coins are produced as a means of deceit, to trick people, buyers and businesses that the coins are legitimate.
It’s understandable to be concerned as a coin collector, as the last thing you want to end up with is a coin that has little-to-no value when you originally believed there was more to it. Before we begin talking about some basic techniques to catching fake coins, it’s worthwhile to consider the three most popular methods in which counterfeit coins are produced.
Cast Fake Coins
One of the simplest and cheapest ways to make a counterfeit coin, cast fake coins are made by pouring a liquid metal mixture into a casted mold of an authentic coin. This is one of the more preferred methods of making counterfeit coins because of the ease it offers to producers, wherein the authentic coin can be readily used to create the exact replica cast–all without causing any damage to the original coin.
The types of metals used in this process will vary, but it is important that producers have a mixture that is good enough to match the surface color of the original. Once the cast has been created, the wanted mixture of metals will be primed, melted and poured into the mold, where it will then sit to become properly cast.
Struck Counterfeit Coins
Struck coins usual make for some of the most unrecognizable counterfeit coins, as the process through which they are produced is quite similar to how mint manufacturers produce their own coins. This type of counterfeit coin is made by placing a planchet–a flat, round metal disc from which a coin is made–between two coin dies. These coin dies are attached to a coining press, which are then pressed against one another, casting the planchet within the mold that is created by the two of them.
Producers tend to make these coin dies by using a number of different methods: the spark erosion method, wherein electromagnetic sparks are used to erode a piece of metal into a specific shape; they might engrave the individual coin faces by hand, manually carving the specific molds before striking their coin; an engraving lathe might be used, which will use a computational software connected to a machine that will create a coin mold using a metal lathe; or they might use the electroless plating method, also known as conversion coating, where the planchet will be submerged into an aqueous solution with deposited nickel, using a catalytic reduction process to create the mold solely through a chemical process.
No matter the method applied to creating the coin mold, these types of counterfeit coins will all be cast the same way, using a coining press to strike the coins. While this creates the most realistic looking coins, it is also the most expensive method to do so and is often reserved for especially rare and valuable coins.
Doctored Counterfeit U.S. Coins
There are two methods to increase the value of a normal coin to something rare and seemingly antique. The first is that a counterfeiter will take a common coin and make minor adjustments to its surfaces to make it appear as if it were a coin of greater value, making slight engravings and etchings to deceive a possible buyer. The second is known as coin “splitting.” This style of producing counterfeit U.S. coins is achieved by taking two coins, splitting them in half, and merging the two halves together. This might seem like a crazy idea, but some more expensive coins can be replicated through this method.
Testing the Dimensions
This is one of the most surefire ways to test for counterfeit U.S. coins, as the U.S. Mint has specific dimensions set for their coins, including: metallic content, weight, diameter, thickness and year of minting. The methods you’ll most easily be able to measure at home are the coin’s weight, diameter and thickness (of which the year of minting will be a visual test). The two devices you’ll need to make these measures are a digital scale and a pair of calipers.
The digital scale is essential to weighing your coin. When shopping for a digital scale, you’ll want to find one that can measure to at least one one-hundredth of a gram (0.01), as you’ll want to ensure that your measurement is as accurate as you can be without requiring high-end scientific equipment.
A small pair of digital calipers is one of the best ways to measure the diameter and thickness of your coin due to their accuracy and precision. While a ruler might work, there is too much human error involved, especially considering how most coins are measured down to hundredths of a millimeter. With calipers, you’ll get a better reading, allowing you to be more certain whether or not you have a fake coin in your possession.
The Visual Tests
When using visual tests to look for counterfeit U.S. coins, it is in your best interest to have a magnifying tool on hand, whether that be a handheld magnifying glass or a jeweler’s loupe. You should first begin by having an authentic coin at the ready, as this will make it much easier to determine any discrepancies between the coin you are assessing and one that is known to be authentic.
The main things you’ll want to look for when examining your coin visually are surface qualities that are mismatching, including: surface texture, text spacing, seams, markings and edges. If you do not have another authentic coin on hand to compare it to, take the time to do your research, either relying on other collectors or collecting guides, which will offer specific details regarding the exact markings you should identify on the coin in your possession. If you happen to find any incongruities, it is likely that you are handling a fake coin.
Checking for Magnetivity
Both gold and silver are non-magnetic metals, meaning they should feel no reaction when a magnet is nearby. There are a number of ways that you can check for magnetivity of your coin, but here are a few of the simplest:
First off, grab a simple magnet and hold it near your precious metal coin. If the coin is even slightly attracted to the magnet, then you know you have a fake on your hand, as metals with contents of iron and steel are the most likely to be attracted. While a simple magnet can work to test this method, use a magnet that is considered high-powered, as you’ll want to ensure that you pick up on any types of trace metals that might be contained within. Neodymium magnets are one of the best magnets you can use to test for trace metals such as iron or steel, and even copper, which only reacts with very strong magnetic fields.
The second option to test for magnetivity is to utilize a magnetic slide. This is a simple slide that can be created at home by using a few magnets that are coupled together at an angle, much like the appearance of a slide. This example is illustrative because both gold and silver are diamagnetic metals—metals that are repelled by large magnetic fields. So, when brought into contact with a number of magnets, these metals will undergo a repellant force.
In the case of being dropped down a slide, a fine, minted gold or silver coin would move slower down the magnetic slide than a counterfeit that contains some other metallic material, primarily due to that repellant magnetic force that counteracts the gravitational force. With just a magnetic slide and a stopwatch, you can test this method at home and see if you have a fake coin!
No, we don’t mean to imply that you’ll need to melt your coin down to determine whether or not it’s a counterfeit, rather you should place an ice cube on the coin to see what reaction you end up with. Sounds strange, right? Maybe so, but this trick comes with scientific reasoning.
Both silver and gold have exceptional thermal conductivity, the ability which a metal has to conduct heat. These two metals have high rates of thermal conductivity at even 20 ℃, with silver being at 419 (W/mᐧK) and gold at 317 (W/mᐧK). Compared to steel, which has a thermal conductivity of 45 (W/mᐧK) and iron at 71 (W/mᐧK), both gold and silver conduct heat much better than either steel or metal.
If you were–at room temperature–to place an ice cube on top of either a coin made out of silver or gold, the ice cube should melt very quickly because the transfer of heat would be quite rapid. If the ice cube melts as if it normally would at room temperature, it might be a sign that you have a fake coin.
How Do I Avoid Buying a Fake Coin?
The $100 question of the day: As a coin collector, how can you be certain that you don’t end up purchasing a fake coin? The simplest answer is to buy from reputable sources. While you might get a deal on a rare or antique coin by buying it from a seller on Ebay or through an antiques shop, the likelihood of the coin being a fake is quite high as you have no way of discerning whether the seller is reputable or not.
When purchasing coins, you want to ensure that you are purchasing them through sellers who have a notable reputation within the field of selling bullion, numismatic coins and more. These are sellers who solely sell minted, certified and .999 fine items of gold and silver. By using this method, you are taking the correct means to guarantee that your purchases are secure and that your coins are legitimate–not counterfeit.
Ed Miller says
I believe original rare coins are being near perfectly copied using same gold or silver materials then encased in the copied ngc and pcgs cases. I bought my coin graded in the case over 10 grand because it looked right and it was in the case right ? Afterwards while rechecking the ngc website I saw that my serial numbers didn’t align similarly with the barcode on the coin in the case that ngc displayed I rechecked with ngc at Whitman show and sure enough that’s what’s going on now. It wasn’t a coin they had graded and the case the coin was in was not theirs either Counterfeiting has gone to a much higher level now
Ed Miller says
Tell them to check the ngc and pcgs websites for the serial numbers of encased coins. Carefully under high magnification Compare your coin with the coin displayed on the website. Also check the alignment of the bar code with the serial number. This is how I suspected and learned I’d been taken on an extremely expensive coin I paid a fortune for since bar code didn’t align with serial number correctly Lastly wait until there’s a Whitman show and only buy from a dealer there.