WHY COINS HAVE RIDGED EDGES
Have you ever noticed that United States dimes, quarters, half-dollars and silver dollars have ridges around their edges? Some people think this is just for decoration, but the ridges were actually designed for a very important reason. When coins were first being made, real gold or silver was used, and the coins did not have ridges. The value of each coin depended on the amount of gold or silver in it.
But some dishonest people played a trick on others to get more money for themselves. They filed off the edges of the coins so that they were no longer worth as much, but then sold them for their original value in gold or silver. To stop this from happening, the government started making the coins with ridges on the edges. If a coin had been filed, it would be easily noticed. Today, our coins are not made of pure gold or silver, but the ridged edges remain, since people are used to seeing them that way.