Final answer:
Hardness, measured on a Rockwell or Brinell testing instrument, refers to a mineral's ability to resist abrasion or scratching. The Mohs' scale of mineral hardness is used to determine hardness values. Understanding hardness is important in determining how an element, especially a metal, can be used.
Step-by-step explanation:
Hardness, measured on a Rockwell or Brinell testing instrument, refers to a mineral's ability to resist abrasion or scratching. It is determined using the Mohs' scale of mineral hardness, which was developed by Frederich Mohs in 1822. The scale is qualitative, meaning there is no quantitative relationship between hardness values.
The Rockwell testing method uses a diamond cone or steel ball indenter to measure hardness, while the Brinell testing method uses a steel ball indenter. The results of these tests are indicated by a number on the Rockwell or Brinell scale, with higher numbers indicating greater hardness.
For example, diamond has a hardness of 10 on the Mohs' scale, making it the hardest mineral, while talc has a hardness of 1, making it the softest mineral. Understanding hardness is important in determining how an element, especially a metal, can be used.