MOHS hardness scale is a measurement scale based on 10 arbitrary minerals numbered from 1 to 10 and is used to measure the hardness of different minerals and objects. In this scale, the hardness is directly equivalent to “the ability to get scratched”.
The ten reference minerals according to the MOHS scale are as follows:
| Mineral | Hardness |
| Talc | 1 |
| Gypsum | 2 |
| Calcite | 3 |
| Fluorite | 4 |
| Apatite | 5 |
| Orthoclase | 6 |
| Quartz | 7 |
| Topaz | 8 |
| Corundum | 9 |
| Diamond | 10 |
Discovery Of Mohs Scale:
The famous scale of hardness measurement was discovered by Freidrich Mohs who was a German mineralogist in 1812. This technique was based on a rather simple concept of the distinct hardness of different minerals. For this purpose, Mohs used 10 different minerals with varying hardness. These minerals ranged from a very soft mineral such as Talcum to the hardest mineral Diamond having a 10 mark on the scale. All the minerals used in this scale are very common to find and easily accessible except diamond which is costly.
For over 2 centuries this method has been used as an effective way to find the relative hardness of minerals, Geologists and students.
How To Perform MOHS Hardness Test?
The test is conducted by placing and holding the specimen on the top of a table, using one hand. Then make contact with the specimen of reference on the unmarked surface of the mineral to be assessed. After this, press the reference specimen firmly on the unknown one and drag it in a direction away from your body. Move it parallel to your fingers in order to avoid any injuries.
How Do You Get To Know The Hardness Level?
As mentioned earlier, 10 reference minerals are granted varying hardness levels. In case you are using reference specimen number 6 and are trying to find the hardness of an unknown mineral then if the reference mineral can leave scratch marks on the unknown mineral its hardness is less or equal to 6. Similarly, if the reference mineral is unable to scratch your unknown mineral then it has a MOHS hardness greater or equal to the #6 mineral. With a couple of tests with varying reference minerals, you can estimate the closest MOH’s hardness.
What Are The Key Points To Measure Hardness Levels?
In the MOHS scale, the hardness is considered as the resistance of a mineral to be scratched and the following points are focused on while comparing a reference specimen and an unknown mineral:
- If two specimens namely 1 and 2 are being used then if 1 can scratch specimen 2 then it is evident that the first specimen is harder than the second one.
- If the first specimen is unable to scratch the second one then specimen 2 is harder than the 1st one.
- Two specimens of equal hardness can be determined by the inability of two minerals to leave prominent scratch marks on one another. Only minor marks might appear with excessive force.
Conclusion:
Therefore, the MOHS scale is an easy and common method to indicate the comparative hardness of two or more minerals. Although this method does not give an exact indication of the hardness level a close estimation can be of great help for Geologists and students. Visit our website for more factual information related to minerals and stuff!
