GEOL 1330 Lecture Notes - Lecture 4: Crystallization, Conchoidal Fracture, Refraction
21 Sep 2016
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Document Summary
Types of minerals that form are dependent on temperature and chemistry. Water that is saturated in a substance will precipitate these ions in solid form (e. g. salt) Minerals consist of an orderly array of atoms (crystalline structure) Chemically bonded to form a particular crystalline structure. Crystalline structure in ionic compounds determined by. Polymorphs: minerals with the same composition but different crystalline structure. Diamond and graphite are both made of carbon. Often highly variable due to slight changes in mineral chemistry. Exotic colorations of certain minerals produce gemstones. Appearance of a mineral in reflected light. Resistance of a mineral to abrasion or scratching. Generally only good for identifying metallic minerals. Cleavage - tendency to break along planes of weak bonding. Described by resulting geometric shape, number of planes, angles between adjacent planes. Fracture - minerals do not break along bonds of weakness. Uneven or curved breakage across strong bonds. Crystal habit, malleability, specific gravity, density, magnetism, reaction to acid, double.
