Have you ever paused to really look at a quarter in your hand? Most of us use coins every day—feeding them into parking meters, tossing them into vending machines, or flipping them to make a quick decision—without noticing the tiny details.

But if you run your thumb along the edge of a dime or quarter, you’ll feel something fascinating: a series of small ridges. They may seem decorative, but these grooves are the result of centuries-old battles against fraud, and their story begins with thieves and a brilliant scientist.

Back in the 1600s, coins were made of precious metals like silver and gold. Thieves discovered a way to profit by shaving tiny slivers from the edges—a crime called “coin clipping.” Over time, they could collect enough of these shavings to melt down and sell, while still spending the clipped coins at full value. The practice grew so widespread that it threatened entire economies, forcing governments to find a clever solution. That solution came in 1696, when Sir Isaac Newton, then Warden of the Royal Mint, stepped in.