How To Check Coins For Authenticity

How To Check Coins For Authenticity

How To Check Coins For Authenticity

November 24, 2023 817 view(s)

Since the world's first coin, the Lydian Stater, debuted around 610 to 600 B.C., people have been fascinated by the world of precious metals. Yet, for an equally long time, unscrupulous parties have been looking to cash in on this intrigue.

At first, counterfeit coins were an attempt to replicate and undermine the artisan's efforts. Counterfeiters would use them to deceive merchants and buyers alike, mixing their forged currency in with authentic pieces. Today, counterfeiting most often occurs in the coin-collecting sector, when plagiarists try to pass their creations off as valuable artifacts. 

Seasoned collectors know to always check coins for authenticity. Yet, these steps can be more complicated than most people realize. As counterfeiters continue to fine-tune their methods, it's also becoming harder and harder to spot a fake. 

Today, we're sharing a few of our top tips to help you distinguish counterfeit coins from the real deal so you can grow your collection legitimately. 

What Makes a Coin Counterfeit? 

Before we dive into how to spot them, let's take a step back. What makes a coin counterfeit in the first place?

In general, this term applies to any coin that someone makes without informing and securing consent from the country or entity that first issued it. While counterfeit coins can have their own unique design, they can also look similar to existing currency. 

For instance, someone might make changes to a standard coin to make it look like a more valuable one. This practice is legal in certain countries, including China, where counterfeiters can make their own replica coins as long as they contain the word "COPY" somewhere on the surface. 

To the untrained eye, these coins can look deceivingly real. This has led many curious coin collectors to spend their hard-earned money on investments that turned out to be corrupt. That's why it helps to know what to search for before you buy. 

Different Types of Counterfeit Coins

With so many different types of coins on the market, counterfeiters have developed a range of techniques to make their wares look convincing. Most of this fraudulent currency falls into one of these three categories: 

  • Struck Counterfeits
  • Doctored Counterfeits
  • Cast Counterfeits

Let's take a look at how these differ. 

Struck Counterfeits

The process required to make a struck counterfeit coin is similar to the one used at a genuine mint. The counterfeiter will start by placing a planchet between two coin dies. A planchet is a flat, round disc used to make coins. 

The dies are attached to a coining press. As they're pressed against each other, it creates a mold into which the planchet is cast. The result is a counterfeit coin that is strikingly similar to a real one.

While this is the basic method, counterfeiters put their own spin on the technique, employing any of several different strategies to create coin dies that appear as realistic as possible. 

The most common tactics include: 

  • Following the spark erosion method
  • Hand-engraving the coin faces
  • Using an engraving lathe
  • Using electroless plating

The spark erosion method requires using electromagnetic sparks to carefully erode a piece of metal into a distinct shape. If the counterfeiter opts for an engraving lathe versus manual engraving, they'll use special software to design the mold, then a metal lathe will cut it. They can also try electroless plating, which is also known as conversion coating. 

With this technique, the counterfeiter will submerge the planchet into a liquid that contains deposited nickel. This triggers a chemical process that creates the mold. As you can imagine, any of these methods can be time-consuming and expensive to follow. That's why most counterfeiters reserve struck fakes for the most valuable coins. 

Doctored Counterfeits

While struck counterfeits are considered the most expensive, doctored counterfeits are the least expensive. This technique simply involves altering or doctoring a surface-level component on a fake coin to make it look real. For instance, a counterfeiter may add a special U.S. mint coming marking to make a coin appear more valuable. 

Another, less-common form of coin doctoring is splitting. With this technique, counterfeiters will take two coins, split them in half, and bond them back together again to give them a different appearance. 

Cast Counterfeits

Another method that counterfeiters use is to make a mold of an actual coin, and then use that mold as a cast to make fake coins. This is a popular route, as it maintains the value and appearance of the host coin. Counterfeiters will pour molten metal into each mold, allowing it to take the shape of its container. 

If they're especially skilled, they may perform this step with a centrifuge so more metal flows to the outer edges of the coin. However, no matter how advanced their techniques might be, this method is usually considered the least realistic and the easiest to detect. 


What to Look For in a Counterfeit Coin

Are you worried that some of the coins in your collection might be counterfeit? Or, are you thinking about buying a new coin but you want to check its authenticity, first? 

Here a the most important factors to consider before making this decision. 

Coin Dimensions

If you're analyzing a U.S. coin, the first place to start is by measuring it. The U.S. Mint sets specific dimensions for all of its coins, including: 

  • Metallic content
  • Coin weight
  • Coin dimension
  • Coin thickness
  • Type of edge
  • Year of minting

While the year of minting is a visible characteristic, you'll need to measure the coin's weight, thickness, and diameter at home. A digital scale is a valuable tool to have on hand for this task, as are calipers. Make sure your scale can measure as little as one one-hundredth (0.01) of a gram.

Calipers will help you measure the coin's thickness and diameter, and allow a more detailed reading than a basic ruler. 


If you have a genuine gold or silver coin, you should not feel a reaction when you place it near any type of magnet. This is because they are both non-magnetic metals.

First, you can simply hold your coin near a magnet and see what (if anything) you feel. If you notice even the slightest bit of pull, you could be working with a counterfeit. In most cases, these inauthentic coins will contain trace elements of other metals, such as iron, which makes them magnetic. 

However, there are some exceptions.

Certain genuine coins (such as the 1943 Lincoln cent) contain steel, which will stick to the magnet. If you're in doubt, check the official specifications for the coin you're examining. In this case, a counterfeit 1943 Lincoln cent that doesn't contain steel wouldn't create a magnetic reaction. 

Another way to test the magnetism of a coin is to create a coin slide. To do so, you'll arrange the coins exactly as the name implies: in a diagonal angle that resembles the shape of a playground slide. When they come into contact with a greater number of magnets like this, both gold and silver coins will have a repellant reaction.

The key factor to consider is speed.

Authentic coins will move slowly down the magnetic slide as the repellant force works against the natural gravitational force. On the other hand, counterfeit coins that contain other types of metallic material won't have as powerful of a reaction and will move more quickly. 

Surface Features 

Next, look at the coin in question under a microscope or a magnifying glass. It helps to have an authentic coin on hand so you can compare the features as you look at them. 

As you peer into the glass, the most important things to look for are surface features that don't quite match those on the real coin. These may include different:

  • Surface textures
  • Coin color
  • Seams
  • Markings (e.g. mintmarks)
  • Text spacing

Types of edges

Don't have an authentic coin on hand? That's OK. You can usually find a detailed, up-close image of the coin online or in special collecting guides, especially if you connect with other coin collectors. 

These images can help you understand the special markings that your coin should have. Pay attention to the level of detail on the coin, especially in these areas:

  • Shape of the letters
  • Details on portraits
  • Position of numbers 

Often, you can spot a dupe due to its simple look and feel, but more sophisticated counterfeits will require a careful examination. 

How To Check  Coins For AuthenticityHow To Check  Coins For Authenticity

Check Coins For Authenticity With Us

While these steps can help you check coins for authenticity, the best way to make sure you're getting the real deal is to purchase your fine coins from a reputable source, like us. 

At the United States Gold Bureau, we have a variety of coins for both new and experienced investors to browse. Our team works closely with the Numismatic Guaranty Corporation (NGC) and Professional Coin Grading Service (PCGS) to guarantee, grade, and certify the authenticity of each coin. These services are industry-recognized for their expertise and each guarantees that the coins it certifies are authentic. 

To learn more and get started, sign up for our free investor guide!