|
|
Mohs Hardness Scale |
Mohs hardness is measured on a scale from 1 to 10 with softer minerals designated by low numbers and harder minerals designated by high numbers. The scale was developed about 200 years ago by Friedrich Mohs.
Mohs scale number (mineral example)
1 (Talc)
2 (Gypsum)
3 (Calcite)
4 (Fluorite)
5 (Apatite)
6 (Orthoclase
Feldspar)
7 (Quartz)
8 (Topaz)
9 (Corundum)
10 (Diamond)
Hardness of other common objects
Fingernail: 2.5
Copper penny: 3
Glass: 5.5
To figure out the hardness of a mineral, try to scratch it with an object of known hardness. For instance, if a fingernail cannot scratch a mystery mineral, we know it has a hardness of more than 2.5. If the mystery mineral can't scratch glass, we know it has a hardness of less than 5.5.
Mohs hardness is measured on a scale from 1 to 10. The scale was made about 200 years ago by Friedrich Mohs. Softer minerals have low numbers and harder minerals have high numbers.
Mohs scale number (mineral example)
1 (Talc)
2 (Gypsum)
3 (Calcite)
4 (Fluorite)
5 (Apatite)
6 (Orthoclase
Feldspar)
7 (Quartz)
8 (Topaz)
9 (Corundum)
10 (Diamond)
Hardness of other common objects
Fingernail: 2.5
Copper penny: 3
Glass: 5.5
To figure out the hardness of a mineral, try to scratch it with an object of known hardness. For instance, if a fingernail cannot scratch a mystery mineral, we know it has a hardness of more than 2.5. If the mystery mineral can't scratch glass, we know it has a hardness of less than 5.5.
A man named Friedrich Mohs knew that different minerals have different hardness! Soft minerals have low numbers. Hard minerals have high numbers.
Mohs scale number (mineral example)
1 (Talc)
2 (Gypsum)
3 (Calcite)
4 (Fluorite)
5 (Apatite)
6 (Orthoclase
Feldspar)
7 (Quartz)
8 (Topaz)
9 (Corundum)
10 (Diamond)
Hardness of other common objects
Fingernail: 2.5
Penny: 3
Glass: 5.5
You can figure out the hardness of a mineral! Try to scratch it with your fingernail. If your fingernail cannot scratch the mineral, you know it has a hardness of more than 2.5. If the mineral can't scratch glass, you know it has a hardness of less than 5.5.
Last modified May 1, 2003 by the Windows Team
The source of this material is Windows to the Universe, at http://www.windows.ucar.edu/ at the University Corporation for Atmospheric Research (UCAR). © The Regents of the University of Michigan. Windows to the Universe® is a registered trademark of UCAR. All Rights Reserved. Site policies and disclaimer