Hardness of a Mineral
One of the most essential and simplest ways of putting a mineral in a general class is by finding out approximately how hard the mineral is in the first place. This can be defined by what type of materials it can scratch and what materials are able to scratch it.
The hardness of the minerals can be rated by Moh’s scale. This scale was developed by a German mineralogist in 1822 whose name was Friedrich Moh. Moh developed a crude but useful technique of comparing hardness or scratch resistance of minerals. However it is not a mathematical progression of relative hardness but only consists of assigning numerical progression to ten different minerals arranged that have different degrees of hardness. This scale goes as follows:
Moh’s Number
- Talc (being the softest)
- Gypsum
- Calcite
- Fluorite
- Apatite
- Feldspar
- Quartz
- Topaz
- Corundum
- Diamond (being the hardest)
Kits of this “scale” can be found in different rock shops and you will be able to test the harness by using them. A lot of prospectors also buy the different types of minerals. Obviously if you buy a gem it can cost you a bundle, but the price will be drastically reduced by buying synthetic gems and small amounts of what you are interested in trying out. Diamond can be acquired in the shape of a little rough diamond that is mounted in a metal bar that is then used to dress grinding wheels. If you ever find yourself out in the field without a hardness kit a lot of common items will give you a approximate estimate of the hardness of most minerals. For example: a toe nail can be equal to 2 and ½, a copper penny is around 3, Glass is around 5, knife around 6, a steel file around 7. Obviously this is only a reference and is refereeing to approximations.
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