The Mohs hardness test is a mineral identification test used to determine the relative hardness of minerals. A Mohs hardness test kit typically includes a set of 10 minerals of known hardness, ranging from soft (talc, with a hardness of 1) to hard (diamond, with a hardness of 10), and a device, such as a scratch plate or fingernail, for making the test. The test is performed by scratching the surface of the mineral to be tested with each mineral in the kit, starting with the softest and moving to the hardest. The mineral's hardness is determined by the mineral that it can scratch, but not be scratched by. The Mohs hardness test is a simple and quick method for mineral identification and is widely used in geological and mineralogical studies.
 
To use a Mohs hardness test kit:
Identify the mineral you want to test and determine its expected Mohs hardness value.
Obtain a set of Mohs hardness reference minerals, typically ranging from 1 (softest) to 10 (hardest).
Clean and dry the surface of the mineral you want to test.
Choose a reference mineral with a known Mohs hardness value that is lower than the expected hardness of your mineral.
Scratch the surface of the mineral you want to test with the reference mineral.
Observe the result. If the reference mineral scratches the surface of your mineral, it is softer than the reference mineral. If it does not leave a scratch, it is harder.
Repeat the process with reference minerals of increasing hardness until you find one that does scratch the surface of your mineral.
The hardness of the mineral you want to test is equal to the hardness of the reference mineral that just scratched it.