1 Duit

The 1 Duit coin from the City of Utrecht (Dutch Republic) was made of copper, which was a common material for coins at that time. However, what's interesting is that the coin was designed with a unique feature - it had a square hole in the center, which was known as a "doughnut hole." This hole was added to the coin to make it easier for people to tell if it was a genuine coin or a counterfeit one. The idea behind this design was that only a genuine coin would have a perfectly round and symmetrical hole, while a counterfeit coin would likely have an irregularly shaped hole. This feature was a pioneering effort in coin design and helped to prevent counterfeiting.