Way back in 1812, a German mineralogist named Friedrich Mohs decided to rank minerals by scratchability. His scale runs from 1 (talc, the softie) to 10 (diamond, the ultimate mean girl).
Here’s the fun part: Your fingernail has a hardness of about 2.5. A copper penny is around 3.5. And a steel knife blade? That’s a solid 5.5. So next time you’re at a dinner party, casually scratch a penny with your nail and whisper, “That’s Mohs 3.5.” Instant charisma.
Cultural reference alert: Remember the “hardness” of The One Ring in Lord of the Rings? It had to be forged in Mount Doom because only that heat could overcome its extreme resistance. That’s fictional Mohs-level drama.
