Earth Sciences 1083F/G Lecture Notes - Lecture 1: Conchoidal Fracture, Sphalerite, Nacre
14 Feb 2017
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Document Summary
The appearance and physical behaviour of minerals are directly related to their chemical composition and bonding characteristics. Calcite is a carbonate mineral and it"s made out of chemicals. Hardness (a measure of the resistance of minerals to abrasion or scratching) Hardness is measured in units of mohs scale of hardness (ability of harder minerals to scratch softer minerals) If a mineral can be scratched by apatite but not fluorite we can say that the mineral must have a hardness between 4-5. Hardness reflects the strength of bonds within a mineral. For some minerals it is hardness that makes them useful to organisms. For example, our bones are made of hydroxyapatite which has a hardness of about 5 (good to make bones and teeth out of) Arrangement patterns of atoms within minerals are revealed in their external crystal form. The packing arrangement of atoms within any given mineral results in a characteristic geometry of crystal faces.
