The Science Tool Box
Scientific equipment and supplies for the lab and schooling.
Please help us maintain this site.



Contact Us
Advertising Rates
Suggest Links
About Us

Mohs' Hardness Scale

In 1812, Friedrich Mohs developed a scale that showed the relative hardness of minerals. The hardness of a mineral could be identified by scratching a smooth surface of the mineral with an object whose hardness is already known.

Level Example Field Test
1 talc leaves soft, greasy flakes on the fingers
2 gypsum easily scratched by a fingernail
3 calcite cuts easily with a nail, can be scratched by a penny
4 fluorite scratched easily by a knife
5 apatite can be scratched by a knife, but with difficulty
6 orthoclase can be scratched by a steel file
7 quartz will scratch a steel file
8 topaz can scratch quartz
9 corundum --
10 diamond --

Familiar objects ranked according to Mohs' Scale of Hardness:

0.7 graphite
1.3 asphalt
2.5 fingernail
3.0 copper penny
3.5 brass
5.5-6.0 knife blade
5.5-6.0 plate glass
6.5-7.0 steel file

Thanks to Anne Wallingford for this reference material.

To contact us, please click Email.


Other Links

© 2004 Arden Services.

Tuesday, October 20, 2009