The Mohs Scale of Hardness is a scale that lists the hardness of minerals from weakest to strongest.
The Mohs Scale was developed in 1812 by a German mineralogist named Friedrich Mohs.
Mohs came up with a main list of ten natural minerals to show their hardness and scratch resistance to each other.
While most of these items on the list are in somewhat of a relative order, the last one, diamond, is an exception.
Diamond is 4 times harder than corundum.
The Mohs Scale of Hardness is as follows…
From one to ten on the scale, we start with…
- TALC – 1
- GYPSUM – 2
- CALCITE – 9
- FLUORITE – 21
- APATITE – 48
- FELDSPAR – 72
- QUARTZ – 100
- TOPAZ – 200
- CORUNDUM – 400
- DIAMOND – 1600 (Numbers after Name are Absolute Hardness)
Comparing these items on the Mohs Scale, you’ll see that there are interesting bigger numbers after the names. Those numbers are the mineral’s “absolute hardness“.
That number is what the hardness of the mineral truly is. Mohs just put them on a scale of 1 to 10 to simplify things and make it easier for people to relate.
But as you can see, diamond is a huge leap above and beyond the entire rest of the list.
Much more than just 10 items:
The Mohs Scale is certainly a much more detailed list than just ten items.
Where do the rest of the gemstones, rocks, minerals and common things fall in line?
Take a peek…
Below is a giant list of items compiled together to form the biggest Mohs Scale list on the net. This is what I call the extended Mohs Scale. It’s huge and fascinating. The complete Mohs Scale list follows…
Extended Mohs Scale list:
What’s this all mean?What all this really means, is that any item on the Mohs Scale list, can scratch any item below it on the scale.
Hence, a fingernail (2.5) can scratch plaster of Paris (2 ). A penny (3) can scratch a pearl (2.5). And platinum (4 – 4.5) can scratch gold (2.5 – 3)… Which is why you shouldn’t wear them side by side.
Another interesting thing about this list is corundum (9). Corundum (or sapphire and ruby) is what most fine watches use for their crystal face. Sapphire crystals are great because they are so high up the scratch resistant list, very little can scratch them (cheaper watches use glass (6 – 7) or plastic (1) as the crystal).
Diamond is King!
So you see, when comparing natural substances to each other, diamond is the king. Diamond is the hardest known natural substance on the face of the earth.
But something is harder…
But when it comes to combining minerals with each other in the laboratory, scientists can actually come up with new man-made synthetic minerals (like aggregated diamond nanorods – 10+) that are harder and more durable than a diamond.
So while a diamond may rule in nature, the labs have got the diamond beat.
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About the Author
Author Richard Scott. Certified Diamontologist and Gemologist. 30 years of experience.
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