What is the hardest mineral?

Diamond is the hardest mineral known to man, according to How Stuff Works. It is assigned a rating of 10 on the Mohs Scale of Hardness, which means that it has the highest resistance to scratching.

The hardness of a diamond is due to its molecular structure. The mineral, which is crystallized under intense heat and pressure over the course of years, is composed of carbon atoms linked together to form tetrahedral units. Every carbon atom in the structure shares electrons with four other carbon atoms, creating a very strong bond and molecule. Diamonds are used to make industrial cutting tools because of their hardness.