How We Authenticate Coins — Clay

When we select coins, they arrive dusty and covered in clay. This is because they've been buried for hundreds of years.

It's not just a light coating! The outer clay coat is like caked on dust. As we get nearer to the metal, it becomes more like dried cement, as it fuses with the coin's patina. The outer layer is easy to remove, the inner layer is quite difficult. When processing our coins, we always remove the outer layers of clay, but how much of the inner layers we remove depends on what we feel makes the coin look most interesting!

When buying coins, we only select samples where we can see the natural progression of these layers (clay, clay fused with patina, patina, metal). In my personal collection, I have some unusual ones which are free of clay -- but when creating products we only go for the coins that I'm 100% sure are genuine.

Fake coins usually have no clay at all. If you covered fake coins with clay, there would be no clear progression between the layers (clay, clay fused with patina, patina, metal), because this takes time to develop. So in other words, it would not be very convincing.

In the image above, all 5 coins are genuine. They have been brushed lightly to remove the outer clay layer, only leaving the cement-like compounds where clay is fused with the patina.