NATS 1870 Lecture Notes - Lecture 14: Gemstone, Ionic Bonding, Covalent Bond
31 Jan 2019
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Tuesday, january 29th: colour in minerals and gemstones. Geodes have rock on the outside and crystals inside. Slight changes of molecular structure change the perceived colour of a substance. Instead of molecules, minerals and gemstones have their atoms arranged into various crystal structures. An example is diamond, and diamonds have the following structure: lattice of carbon atoms with shared e- (large collections of atoms bonded together within a repeating, regular structure). Within the crystal structure, some e- are shared widely. Instead of discrete energy levels/ orbits, the e- can take on ranges of energies: these are called energy bands. Minerals: natural occurring solids, possess an orderly internal structure, atoms are arranged in a definite patter, they have a definite chemical composition, typically formed when rock or magma cool. Gemstones: a type of mineral, when cut and polished, can form a gemstone with brilliance and luster, examples include ruby, sapphire, emerald, aquamarine, garnet, peridot, and amethyst.
