Run your thumb along a quarter’s edge and you’re touching the ghost of an old financial crisis. In the 1600s, coins were made of real silver and gold, and criminals shaved their edges to steal metal while passing off the lighter coins at full value. The practice grew so widespread it endangered entire economies, forcing governments to rethink how money itself was made.

Isaac Newton, serving as Warden of the Royal Mint, helped turn a simple idea into a powerful safeguard: add ridges to the coin’s edge so every cut, every theft, left a visible wound. Clipped coins instantly betrayed themselves. That design still shapes modern currency. Even though today’s quarters and dimes hold no silver, their edges preserve security for banks and machines, tactility for the visually impaired, and a physical link to history. In a world racing toward digital money, those ridges remain a quiet, stubborn memory of why trust in currency had to be engineered, not assumed.