GEOLOGY

Detailed explanation-1: -Explanation: Hardness is a relative property. If talc has H=1 and Quartz H=7, it does not indicate quartz is seven times harder than talc. Explanation: Cleavage is defined as the tendency of a crystallized mineral to break along certain directions yielding more or less smooth, plane surfaces.

Detailed explanation-2: -Hardness is just one mechanical measurement and properties such as toughness and strength need to be considered, as hard materials tend to have low toughness and can easily fracture. Hardness can be assessed by a number of techniques including indentation, scratch and rebound hardness measurements.

Detailed explanation-3: -Hardness. The ability to resist being scratched-or hardness-is one of the most useful properties for identifying minerals. Hardness is determined by the ability of one mineral to scratch another. Federick Mohs, a German mineralogist, produced a hardness scale (table 5) using a set of ten standard minerals.

Detailed explanation-4: -In some minerals hardness is very dependant on direction, since hardness is a vectorial property. When there is significant difference in hardness in different directions, it can be a very diagnostic property of the mineral.