How many ridges (often called 'reeds') are on the edge of the U.S. 25 cent coin, the quarter?

There are 119 ridges or reeds on the edge of a quarter, 118 on the dime and 150 on the edge of the half dollar (mostly now a collectible).

The 1792 Coinage Act established the U.S. Mint and specified that $10, $5 and $2.50 coins (known as eagles, half-eagles and quarter-eagles) were to be made of their face value in gold, while dollar, half-dollar, quarter-dollar, dime and half-dime coins were to be made of their value in silver. Cent and half-cent coins were made of cheaper copper.

Criminals saw that they could make a good profit by filing shavings from the sides of gold and silver coins, selling the precious metal. Before the 18th-century was out, the U.S. Mint began adding ridges to the coins’ edges, a process called “reeding”, in order to make it impossible to shave them down without the result being obvious. The reeded edges also made coin design more intricate and counterfeiting more difficult.

The U.S. Mint stopped producing all gold coins during the Great Depression, after an executive order from President Franklin D. Roosevelt. A silver crisis in the 1960s led that metal to be gradually phased out as well. Today’s coins contain no precious metals but those ridges, at least on half-dollars, quarters, dimes and some dollar coins are still there. This is primarily to make the coins distinguishable from each other, by feel as well as appearance, enabling visually impaired people to tell the difference between similarly sized coins, like the dime and penny.