In numismatics, there is a constant battle against the proliferation of counterfeits. With technology advancing at an exponential rate, the counterfeiters are unfortunately able to more accuratelyreplicate collectible coins.

This arms race between counterfeiters and authenticators is making the coin market an increasingly dangerous place. Most notably, there has recently been an increase in high-quality transfer diecounterfeits into the marketplace. These fakes are made by essentially cloning a genuine coin. One such example of a coin that has been "cloned" in this way is the 1825 Bavaria Coronation Thaler(below).

It is clear from the photos above that these are two very different coins. There are many differing marks and scratches, and the toning is different on both. However, note the areas circled inred. These highlight marks and abrasions that are not inherent to the original design of the coin and yet are still visible on two separate examples.

Authenticators know that it is extremely unlikely for two genuine coins to have contact marks in the exact same locations, so if two coins show identical abrasions, there is a very good chancethat they are fake. These recurring marks are known as "repeating depressions" and are commonly seen on transfer die counterfeits. They occur when any abrasions or imperfections on the"host" coin are transferred to the false die. These imperfections are then struck directly into every coin those counterfeit dies strike.

To read the complete article, see:
Counterfeit Detection: 1825 Bavaria Coronation Thaler (https://www.ngccoin.com/news/article/6186/counterfeit-taler/)