Why are diamonds so good at cutting things answers?

Because they have sharp edges

Diamonds are so good at cutting things, because they are very hard minerals. They can cut other minerals, but other minerals can’t cut them. Out of all the different kinds of minerals on the Mohs’ hardness scale, diamonds rank right at the top, at the hardness of 10. That means, that they are the hardest out of all of the other minerals. The higher the number, the harder it is to be cut.