It takes a huge amount of pressure to break a diamond. Diamonds are made of carbon, and they’re hard because the atoms in them are arranged in a very regular pattern. That’s why they’re so hard: They’re like a huge number of little bricks stuck together.
But when you apply enough pressure, even those tiny bonds can break. And that’s what happens when you cut diamonds: You’re breaking their bonds.
Diamonds have a hardness of 10 on the Mohs scale, which means they scratch glass, which has a hardness of 7. So it takes about 10 times more pressure to scratch a diamond than it does for glass to scratch it.
Diamond is one of the hardest substances on Earth (along with some others like silicon carbide). The Mohs scale measures hardness by using an instrument called an abrasive microhardness tester (or just abrader) that applies increasing amounts of pressure until something is scratched or broken.
Last modified: November 18, 2022