GEOLOGY

Detailed explanation-1: -Explanation: Hardness may be defined as the resistance, which a mineral offers to an external deformation action such as scratching, abrasion, rubbing or indentation. Hardness of a mineral depends on its chemical composition and atomic constitution.

Detailed explanation-2: -Since hardness depends upon the crystallographic direction (ultimately on the strength of the bonds between atoms in a crystal), there can be variations in hardness depending upon the direction in which one measures this property.

Detailed explanation-3: -Crystal form, cleavage, and hardness are determined primarily by the crystal structure at the atomic level. Color and density are determined primarily by the chemical composition. Minerals are classified on the basis of their chemical composition.

Detailed explanation-4: -Hardness is a mineral’s ability to resist being scratched. Minerals that are not easily scratched are hard. You test the hardness of a mineral by scratching its surface with a mineral of a known hardness. Mineralogists use the Mohs Hardness Scale, shown in Table below, as a reference for mineral hardness.

Detailed explanation-5: -Mineral Structure A mineral species is defined by two distinct properties: (1) its chemical com-position and (2) its crystal structure. Each mineral has a distinct three-dimensional array of its constituent atoms. This regular geometry affects its physical properties such as cleavage and hardness.