ERS120H5 Lecture Notes - Lecture 6: Covalent Bond, Microcline, Feldspar
Document Summary
Mystery mineral # 2: colour: purple quartz! why does quartz have these properties, chemical composition and structure has to do with internal structure. Start with basic building block and silica tetrahedra. This causes these 2 outer shells to share electrons: covalent bonds: atoms that share electrons to make themselves more stable & strong. Shape of molecule: tetrahedral (4 sides: e. g. quartz : has a framework silica oxygen bonds with silica in 2 directions allows it to be stable, properties of quartz. Hard, strong, durable: in every direction it has strong covalent bonds make it hard of about 7, equibatious. Oxygen and silicon make up 3 quarters of everything on earth (2:1 ratio 2 oxygen and 1 silicon) Irregular fracture weakly bonded in every direction therefore can break it anyways therefore no cleavage. Low sillican oxygen has lots of iron and magnesium. Grows into elongated, striated crystals, 2 cleavages. Stubby and striated crystals still elongated yet not as much.
