The name of the commonly used hardness scale is:

Explanation:

Mohs scale is defined as a scale which distinguishes minerals on the basis of its hardness.

Minerals which are classified with the help of this scale are placed from 1 to 10. The hardness of minerals increases with increase in number at which they are placed.

For example, talc is placed at number 1 and diamond is placed at number 10.

This shows that diamond is the hardest mineral present and it does not get a scratch.

Therefore, we can conclude that the name of the commonly used hardness scale is Mohs scale.