Everybody knows that diamonds cannot be scratched, but what about all the other minerals? Where on the scale do they fall as far as hardness?

It turns out that this property was studied by German mineralogist Friedrich Mohs in 1812. He created a scale that ranked the minerals according to whether they could scratch another mineral. The scale is not linear and the difference between 9 and 10 is greater than 9 and 1! 

For this graphic, I collected 100 well-known minerals and gems and ranked them in a spiral, ending with diamond in the middle. With a Mohs number of 10, diamond ranks at the maximum end of the scale. Not surprisingly, soft talc is the lowest mineral, with a rank of 1. A quick glance at the spiral and you will see that more expensive and coveted jewels usually have a higher hardness rating.