Diamonds Are the Hardest Naturally Occurring Substance in the World

Diamonds are the hardest naturally occurring substance. You can't scratch a diamond except with another diamond you can. hardness is whether something can be scratched and toughness is whether it shatters into a thousand pieces if you hit it with something. So diamonds, because the layers of carbon are very tough, you know, internally, but you hit them with a hammer. Bang. Smashes.