How to Detect Counterfeit or Altered Coins 

How to Detect Counterfeit or Altered Coins 

This is a basic guide to help you determine if a coin is authentic, this guide in no way replaces years of experience in counterfeit detection. 

What is a Counterfeit Coin? 

A counterfeit coin is a coin that has been reproduced to make the collector believe it is the genuine coin.  These are typically easier to detect, and will have more flaws to help you detect these coins. 

What is an Altered Coin? 

An Altered Coin is an actual government produced coin that has been altered either by adding material or removing material to get the desired coin.  Example, 1928S Peace Dollar in XF Condition retails for about $65, if you were to remove the S Mint Mark, the 1928 Peace Dollar in that condition is worth about $550.00. 

How to Detect a Counterfeit Coin? 

1)      Weight – Find out the weight of the genuine coin, genuine coins rarely vary more then 1%, while Cast Counterfeits may be 5% to 10% lighter then a genuine coin.

2)      Strike – Look at the fine detail of the coin (small lines, hair, etc) if lines run together and lack detail or if the overall design of the coin looks weak, and the detail looks mushy, this is not a good indication of a genuine coin. (Figure 1 -1 )

3)       Raised Area in Fields – Since the coin should have been struck, the fields (non design areas) should be flat.  These areas of the coins should not have raised material, or lines. (Figure 1 – 3)

4)      Color – Color alone is difficult to determine if the coin is genuine or not, but it can help.  If the coin looks like an Uncirculated or Almost Uncirculated coin, yet has no mint luster, or a dull finish, this is a good indication it this coin is not genuine.

5)      Rarity – This is a basic guide that will help you, if the coin is a very common date coin, and has very little value, these coins tend to be genuine.  Larger size gold coins tend not to be counterfeited unless they are a rare date. Small size gold coins are more likely to be counterfeited. 

How to Detect an Altered Coin? 

1)      Date – First look at the date and check you see if there is damage around the date.  Look at the individual numbers to see if the shape and design are correct.  You should be able to take another coin of that type to check to see what the numbers should look like. (Figure 1 -2 )

2)      Added Mint Mark – You should look at the mint mark, and see if it is in the correct position and see if the Mint Mark is the correct shape.  Look to see if the Mint Mark is clear and sharp, mushy Mint Marks tend to indicate an added Mint Mark.  Look around the Mint Mark to see if it is sitting in a small depression, which is a good indication of a genuine coin.

3)      Removed Mint Mark – You should look where the Mint Mark should be on the coin and look for tool marks, damage, or some remaining Mint Mark.  Roll the coin in the light, to see if you can see any remaining part of a Mint Mark.  Usually, if they removed a mint mark, that section of the coin will be lower than the rest of the coin. 

Figure 1-1

Figure 1 -2