What is hardness?
The ability of a material to resist damage as a result of bending, scratching or cutting.
What is Mohs' Scale of Hardness?
Friedrich Mohs was a German scientist who lived from 1773 to 1839.
He invented a simple relative hardness scale and scratch test to help tell the difference between minerals.
Mohs' scale is made of ten minerals that are arranged in order of hardness.
Diamond is hardest mineral on our planet. It is given the number 10.
Talc as the softest mineral and is given the number 1.
Mohs' hardness scale is a relative scale.
That means it can only tell you that one mineral is harder than another mineral. The problem is that it cannot tell you how much harder.
It works like this:
Gypsum has a hardness of 2. It can only scratch talc with a hardness of 1.
Corundum has a hardness of 9. It can scratch all the other minerals except diamond with a hardness of 10.
What is a relative Scale?
Let's take the size of the planet Earth compared with the Sun.
A relative scale would tell us that the Sun is bigger than the earth.
An absolute scale would tell us that the diameter of the Sun is 109 times wider than the Earth's.