The Why of Ridged Coins

Articles on this blog are often about the why of things. For example, I was sorting coins that I had gathered in a jar and wondered why of the four coins that are in wide circulation in the United States today, the dime and the quarter have a ridged edge, and the penny and nickel are smooth. 

According to the U.S. Mint, those ridges are technically called a reeded edge. Is this a decorative or practical difference? But is the reeded edge purely decorative, or does it serve a purpose? 

As a kid, I'm sure someone told me is was so that blind people could distinguish coins, but I found no evidence of that being a reason, though it certainly might be a use for the ridges.

When the U.S. Mint opened in Philadelphia in 1793, the coins it produced were made of copper, silver, and gold, in accordance with the Coinage Act of 1792. Because coins of this era were made of precious metal, they were vulnerable to a practice known as clipping, which involved cutting off a small portion around the circumference of the coins. A skilled clipper would shave off enough from the coins to eventually amass a quantity of scrap metal worth cashing in, while also ensuring that the coins weren’t conspicuously reduced in size or weight, allowing the altered coins to still be spent.

Clipping had been common in 17th-century Europe, and it was so prevalent in England that by the end of that century, almost half of the silver content was absent from circulating English coins. This resulted in the metal composition of the coins being lower than their face value, a discrepancy that threatened to create a financial crisis throughout the continent, as well as in the European colonies. In order to combat the practice, England began minting coins with ridged edges; a smooth edge on any part of a coin would then be a telltale sign of clipping. When the United States was founded as an independent nation, the U.S. Mint followed suit by designing its higher denomination coins with reeded edges right from the beginning.

Since today's coins are not made with precious metals, the practice is a vestige of a past practice. Today’s U.S. circulating coins are mostly “clad” coins — a copper core sandwiched between other metal layers — except for the nickel. The Mint switched to clad coins as silver and gold got too expensive. The 1970 half dollar was the last circulating coin with silver. There are collector versions of dimes, quarters, and half dollars that are still made in 99% silver, but those aren’t for everyday use. On the edge of a quarter or dime, if you see a reddish line, it is the copper core peeking out. The nickel is the oddball since it is a solid alloy with no layers.