Which mineral is the hardest naturally occurring substance on the Mohs scale?

Diamond is the hardest naturally occurring mineral on the Mohs scale, where it is assigned a value of 10. The scale was created by Friedrich Mohs in 1812 to compare scratch resistance between minerals. Diamond’s exceptional hardness comes from its crystal structure, in which each carbon atom is strongly bonded to four others in a tetrahedral arrangement. This makes it extremely useful not only in jewelry but also in cutting, drilling, and abrasive tools. Hardness is different from toughness, so diamond is hard but can still be cleaved along specific planes.