The ridges on the edge of coins
Have you ever noticed that dimes and quarters are all rough around the edges and have ridges while nickels and pennies are smooth and ridgeless? Well, there’s a perfectly good explanation for this situation.
In the past, coins had different types of metal cast and different weights, which represented their true value. For instance, one silver dollar was stamped from one troy ounce of 99.9% pure silver. To save up and melt as much silver as possible and transform into new coins, people started clipping their edges.
To prevent them from making other coins, minters started making ridges on the edges of precious metal coins to be able to distinguish between a counterfeit coin and a real coin.
Read also: 21 Things You Should Never Buy From Someone You Don’t Know