What mineral is commonly used to define the hardness scale in geology?

The mineral commonly used to define the hardness scale in geology is talc. The Mohs hardness scale ranks minerals based on their ability to scratch one another, and talc is assigned the lowest value of 1. This means that talc can easily be scratched by all other minerals on the scale, establishing it as the baseline for assessing relative hardness in geological studies.

This scale progresses from talc at the soft end to diamond at the hardest end, demonstrating the variety of hardness among different minerals. Other minerals mentioned, such as quartz and gypsum, occupy different positions on the scale, with quartz at a hardness of 7 and gypsum at 2, while diamond is at the top with a hardness of 10. Understanding the hardness scale is fundamental in geology since it helps identify minerals based on their physical properties.