Earth Sciences 1022A/B Lecture Notes - Lecture 2: Ionic Bonding, Biotite, Amphibole
8 Oct 2016
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Document Summary
Minerals: solid chemical compounds that combine to form rocks o o o. Vary in atomic bonding, molecular structure and element composition. Therefore they differ in their chemical and physical properties allowing for identification. Only around 20 minerals dominate the earth"s crust. Common minerals: natural solid compounds found commonly in the earth"s crust. Made up of silicon-oxygen tetrahedron (silica, sio4. Bounded to various metallic cations to form a mineral. Covalently-bonded silica tetrahedral surrounded be fe, mg cations. Fe and mg substitute for each other to form a group of minerals. Single chains of tetrahedra ionically bonded to metallic cations: nearly right angle cleavage. Amphibole (see diagram: double chains of tetrahedra ionically bonded to metallic cations o. Biotite (see diagram: tetrahedral sheets ionically sandwich k+ o. Strongly bonded 3d network of silica tetrahedra: orthoclase: k+ group, plagioclase: ca-na group. Quartz: made entirely of silica tetrahedra (sio2) o.
