If chalk is such a dense rock why is it so soft/weak?

Question

For example iron is really dense and it’s density seems to be the reason it’s such a strong material, why is the same not true for chalk?

I looked at a chart and chalk is much more dense than so many other types of rock, all of which are much stronger than chalk and could be used practically as building materials etc. But chalk is so soft? Is it because of the porosity? Or structure? Idk

In: 7

Answer 1

Density is how tightly packed the atoms are, hardness is how tightly the atoms grip each other.