What is the relationship between density and hardness?

Answer 1

I dont think they are. Hardness is dependent on ductility, elastic stiffness, plasticity, strain, strength, toughness, viscoelasticity, and viscosity. Density is a function of mass and volume.

Answer 2

No. This can be seen by comparing various objects. Diamonds are commonly called the "hardest" substance. If you rub a diamond firmly against another material, the diamond will leave a scratch, and the diamond itself will be unmarked. Harder substances will scratch softer substances without leaving any of the harder material behind on the softer material, and without scratching or marking the harder material in any way. Gold is a dense material. It is FAR denser than a diamond. However, gold is so soft, that most things will scratch gold. Rocks come in all ranges of density and hardness. It is so practical, that an entire identification system has been set up to figure out what mineral a rock contains based on what will scratch the rock, and what color material will be left behind if the rock is rubbed against a white, ceramic tile. Most of the time, harder things are also denser, but as the example of gold and diamonds shows, this is not a rule, and therefore, the two have nothing to do with each other per se.

Answer 3

Stiffness is a resistance to deformation in response to a force, as opposed to flexibility. Hardness is a more broad concept, relating to how resistant the material is to permanent shape change.

For example, a material can be stiff (not flexible) and brittle, meaning that a small force can fracture it - therefore, it has low hardness.

Another material can be flexible (not stiff) but with high elasticity, meaning that it is difficult to cause permanent changes to its shape - therefore, it technically is harder.

Because it envolves different concepts, hardness is often related to which kind of test is being used to measure it (scratch hardness, indentation hardness, etc). Different methods can yield completely different values of hardness.

Answer 4

Hardness refers to a mineral's resistance. Density is the measure of how much matter there is.

Answer 5

Density is one of the properties of matter. It is a measure of how tightly the molecules are packed together.

Answer 6

Hardness refers to a minerals resistance to scratching. Brittle refers to the tendency of a material to fracture with little or no distortion.

Answer 7

well, it is because density has mass and it means mass per volume gl :)