hardness

As a noun hardness

is the quality of being hard.

As an adjective superhard is

having a very high hardness.

As nouns the difference between hardness and microhardness

is that hardness is the quality of being hard while microhardness is the hardness of a very small area of the surface layer of a material.

As nouns the difference between hardness and hydrotimetry

is that hardness is the quality of being hard while hydrotimetry is (chemistry) the measurement of the hardness of water by titration with a soap solution.

As a noun hardness

is the quality of being hard.

As an adjective ultrahard is

extremely hard; of utmost hardness or ultrahard can be harder than diamond, harder than 150gpa resistance.