The range of numbers for the Mohs scale of mineral hardness is from 1 to 10.
Understanding the Mohs Hardness Scale
The Mohs scale of mineral hardness is a fundamental tool used to assess the scratch resistance of various minerals. As indicated by the reference, it is a qualitative ordinal scale that runs numerically from 1 to 10. This scale allows minerals to be characterized by their ability to scratch or be scratched by other materials on the same scale.
How the Scale Works
The principle behind the Mohs scale is simple: a harder material can scratch a softer material, but a softer material cannot scratch a harder one. The scale assigns a numerical value, or hardness rating, to minerals based on this property.
- 1: Represents the softest minerals.
- 10: Represents the hardest minerals.
It's important to note that this is an ordinal scale, meaning it ranks materials in order of hardness but does not represent a linear or proportional increase in hardness between numbers. For instance, the difference in absolute hardness between a mineral rated 9 and one rated 10 is much greater than the difference between a mineral rated 1 and one rated 2.
The Scale's Range in Detail
The established range of the Mohs scale is precisely defined:
| Mohs Hardness Number | Mineral Example | Scratch Resistance |
|---|---|---|
| 1 | Talc | Easily scratched by fingernail |
| 2 | Gypsum | Can be scratched by fingernail |
| 3 | Calcite | Can be scratched by a copper coin |
| 4 | Fluorite | Can be scratched by a steel knife |
| 5 | Apatite | Can be scratched by a steel knife |
| 6 | Feldspar | Can be scratched by glass |
| 7 | Quartz | Scratches glass; cannot be scratched by steel knife |
| 8 | Topaz | Harder than quartz |
| 9 | Corundum | Harder than topaz |
| 10 | Diamond | The hardest known natural mineral |
This table illustrates that the scale begins with the softest mineral assigned a value of 1 (like talc) and ends with the hardest natural mineral assigned a value of 10 (diamond).
Practical Applications
The Mohs scale is widely used in:
- Geology: Identifying minerals in the field.
- Gemology: Assessing the durability and scratch resistance of gemstones.
- Manufacturing: Determining the suitability of materials for specific applications (e.g., abrasives, cutting tools).
- Education: Teaching fundamental properties of minerals.
By referencing the standard numerical range from 1 to 10, professionals and enthusiasts can compare the relative hardness of different substances efficiently. The reference clearly states this specific range as the basis for the Mohs scale's characterization of scratch resistance.
