EPSC 201 Lecture Notes - Lecture 3: Crystal Growth, Diffraction, Chemical Formula
4 Sep 2018
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Document Summary
Rocks and minerals: interude a rock groups goes with chap 3 minerals. Naturally occuring solid formed by geographic processes that has crystalline structure and definable chemical composition. Geographic processes could be: freezing from melt, precipitation, chemical reactions. Most rare, common ones found in rocks and sediments. Xray beam passing through crystal breaks up into beams to make dot pattern diffraction. Each atom bonds to 4 neighbours arranged in form of tetrahedon. Covalent bonding of 3 carbon atoms within each sheet. Shape of single crystal with well-formed faces, or many well-formed crystals that grew together as group. Cleavage is tendency for a mineral to break along lattice planes with weaker atomic bonds. Silicates: most common, dominate crust and mantle, quartz. Sulfides: metal cations bonded to sulfide anion, pyrite. Native metalspure masses of a single metal, copper, gold. Native elements pure masses of a single element, diamond. Coherent holds together, can be broken into separated pieces.
