Why do coins have ridges on the edges?

To stop coin clipping. When coins were made of silver and gold, people shaved slivers of metal off the smooth edges and spent the coin at full value. Ridged edges made any clipping instantly visible, because the pattern would be cut away with the metal.

How many ridges does a quarter have?

A US quarter has 119 reeds around its edge, and a dime has 118. The counts are fixed in each coin's official specifications.

Why are pennies and nickels smooth?

Because they never contained precious metal. With nothing valuable to shave off, clipping was pointless, so those denominations never needed the anti-theft edge.

Do coin ridges still serve a purpose?

Yes, just not the original one. Reeding makes coins harder to counterfeit and lets people with visual impairments tell denominations apart by touch, which is why mints kept it after the silver left.

When did US coins stop being silver?

The Coinage Act of 1965 removed silver from dimes and quarters, which had been 90 percent silver, replacing it with layers of copper-nickel over a copper core.

Why Do Coins Have Ridges? Blame the Coin Clippers

Run a thumbnail around the edge of a quarter and you will feel them: tiny, even grooves, all the way around. There are exactly 119 on a quarter and 118 on a dime. Now check a penny and a nickel - smooth. That difference is not decoration. It is the fossil of a crime wave.

Why do coins have ridges?

Because coins used to be made of silver and gold, and people shaved slivers of metal off the edges, then spent the lightened coin as if it were whole. Ridged edges, called reeding, made the theft self-reporting: clip a reeded coin and the missing pattern gives you away at a glance. The silver is long gone from pocket change; the anti-theft device remains.

The crime: clipping

For most of the history of money, a coin’s value was the metal in it. A silver coin was a government-stamped promise that this disc contains this much silver. Gold made the same promise from a thin supply: almost all of Earth’s gold sank into the core as the planet formed, and every gold coin ever struck came from the percent or so left outside it.

That promise had an exploit. Early coins were struck by hand with a hammer, so their edges came out slightly irregular anyway. Shave a whisper of silver from the rim - not enough to notice - and pass the coin on. Do it to a thousand coins and you have a pile of silver dust that came from everyone else’s pockets. Clipping was so common that badly clipped coins could lose a serious fraction of their weight as they circulated, which meant the coin in your hand was routinely worth less than it claimed. Everyone shaving a little off a shared stock does the same work outside money, which is how a sturgeon fishery landing seven million pounds a year in the late 1800s ended in a ban on catching the fish at all.

Every person who accepted a clipped coin was being robbed of the difference. Which is why governments treated clipping not as mischief but as an attack on the currency itself.

Isaac Newton, fraud investigator

The fix arrived with machine-struck coinage, and one of its most famous enforcers was Isaac Newton. In 1698, during his time as warden of the Royal Mint, reeding was implemented on English coins - a precise, machine-cut pattern around the edge that no clipper could restore with a file.

The logic is elegant: you cannot shave the edge without removing the ridges, and you cannot fake the ridges by hand. The edge became a tamper seal. Newton, who spent his later career running the Mint and pursuing counterfeiters with the same thoroughness he had applied to gravity, helped make the coin itself testify against the criminal.

Why the penny never got them

Reeding tracked the precious metal, denomination by denomination:

Coin	Edge	Reason
Dime	118 reeds	Was 90% silver
Quarter	119 reeds	Was 90% silver
Nickel	Smooth	Never precious metal
Penny	Smooth	Never precious metal

Nobody clips a coin whose metal is worth less than the effort. So the cheap denominations stayed smooth, and the silver ones got armor. In 1828 the U.S. Mint’s close collar method made the reeding automatic and perfectly uniform, which is why every dime since has the same 118 grooves.

Then the reason evaporated. The Coinage Act of 1965 pulled silver out of dimes and quarters entirely, replacing it with copper-nickel layers over a copper core. There has been nothing worth shaving off a quarter for six decades.

Every quarter in your pocket wears armor against a crime that has been impossible since 1965. The threat died; the ridges shipped anyway, billions of times a year.

Why they are still there

Partly because standards outlive their reasons - the QWERTY keyboard is the same story told in letters instead of grooves. But reeding also picked up honest second jobs: it makes coins harder to counterfeit, and it lets people with visual impairments distinguish a quarter from a nickel by touch alone. A security feature from the age of seasonal hours and sundial time turned out to be good accessibility design three centuries early.

So the ridges are a message, if an accidental one: this object was once treasure, worth stealing a sliver at a time, and the mint won the arms race so thoroughly that we forgot there was ever a war. Count them yourself - all 119. Strictly FYI.