Rosiwal scale

The Rosiwal scale is a hardness scale, with its name given in memory of the Austrian geologist August Karl Rosiwal. The Rosiwal scale bases its measure on absolute values, unlike the Mohs scale whose values are relative values, its interest is relegated to the amateur or an approach that makes it useful in the research field ('in situ').[1]

The Rosiwal method (also called Delesse and Rosiwal) is basically a method of petrographic analysis and led to the development of the stereograph.[2][1]

Rosiwal scale values

Valor MOHS Mineral ROSIWAL value Chemical
composition
Hardness 1 10 100 1.000 10.000 100.000 1000000
1 Talc****Mg3Si4O10(OH)2
2 Plaster******CaSO4 · 2H2O
3 Calcite**********CaCO3
4 Fluorite**********CaF2
5 Apatite***********Ca5(PO4)3(OH−,Cl−,F−)
6 Feldspar**************KAlSi3O8
7 Quartz****************SiO2
8 Topaz******************Al2SiO4(OH−,F−)2
9 Corundum********************Al2O3
10 Diamond********************************C
Mineral
Mohs scale Degree
   Rosiwal hardness  
  Talc 
1°
0.03
  Plaster 
2°
1.25
  Calcite
3°
4.5
  Fluorite
4°
5
  Apatite
5°
5.5
  Feldspar  
6°
37
  Quartz
7°
120
  Topaz
8°
175
  Corundum
9°
1,000
  Diamond
10°
140,000

Measures in an absolute scale the hardness of minerals expressed as abrasion's resistance, measured at laboratory, starting with corundum with a base value of 1000.

Comparison Mohs scale and Knoop.

Knoop scale

The Rosiwal scale is used in mineralogy in the same way as Mohs scale and Knoop scale.

See also

References

Notes

  1. 1 2 D H Maling (24 September 2013). Measurements from Maps: Principles and Methods of Cartometry. Elsevier. pp. 437–. ISBN 978-1-4832-5767-9.
  2. ↑ Rosiwal method

Bibliography

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