Interesting Facts Interesting Facts

What is the Mohs scale of mineral hardness?


In 1812 the German geologist and mineralogist Friedrich Mohs defined the hardness of different minerals based on the ability of one material to scratch another softer material. The higher the number the harder the mineral in a range of 1 – 10 and each value is twice as hard as the one below and half and hard as the one above.

An example is Topaz. It has a Mohs scale of 8, Corundum is 9 and twice as hard as Topaz. Diamonds have a Mohs value of 10 and are four times as hard as Topaz.


Here is a list of Minerals and their Mohs hardness


Talc                                            1

Gypsum                                      2

Calcite                                        3

Fluorite                                       4

Apatite                                        5

Orthoclase Feldspar                   6

Quartz                                        7

Topaz                                         8

Corundum                                  9

Diamond                                    10


There are minerals that are positioned between these numbers like Pyrite (fools gold) at 6½ and Gold and Silver at 2½.