1MineralsMineral• Naturally occurring• Inorganic•Solid• Regularly repeating internal arrangement of atoms• Definite chemical compositionRocks may be composed of minerals and/or other material Periodic tableAtomic structure ATOM FEATURES• Nucleus contains both protons and neutrons• Each atom of an element has the same number of protons in the nucleus• Different atoms of the same element may have different numbers of neutrons in the nucleus• These differing-neutron atoms are called isotopesShells of electronsELECTRON FEATURES• Electrons occur in a cloud around nucleus• More likely to occur at certain distances and with a certain amount of energy than in other places—the energy shells• Inner shells fill before outer shells are created• Full shells more stable than partial shellsPERIODIC TABLE• Arranged from lowest atomic number to highest, from left to right, from top to bottom• Each row corresponds to an energy level (electron shell)• Each column contains elements with similar properties, which repeat on a regular (or periodic) basis• These similar properties are a result of the same number of electrons in the outermost shellPeriodic table2Ionic bonding• Result of stability of filled outer shells of electrons• Sodium apt to lose its lone outer electron• Chlorine apt to fill its nearly-full outer shellElemental Abundance in CrustSilica tetrahedronIsolated and chain Silicate StructureOlivine crystal HornblendeSheet silicate structure Cleavage—mica Framework silicate structure3Potassium Feldsparhttp://www.pitt.edu/~cejones/GeoImages/1Minerals/1IgneousMineralz/Feldspars.htmlQuartz: conchoidal and irregular fracturehttp://www.pitt.edu/~cejones/GeoImages/1Minerals/1IgneousMineralz/Quartz.htmlIMPORTANT MINERAL PROPERTIES• LUSTER: all minerals have it• CRYSTAL FORM: some show it • STREAK: color may be white• COLOR: may be diagnosticQuartz crystals Pyrite crystals Pyritohedrons• Five sided faces• Ten faces• Often striated• http://www.dorlingkindersley-uk.co.uk/nf/ClipArt/Image/0,,239020_1581737_,00.html• http://www.minerals.net/mineral/sulfides/pyrite/pyrite2.htmHornblende Fluorite crystals streak4Color may not help to identify mineral• These are all quartzhttp://www.pitt.edu/~cejones/GeoImages/1Minerals/1IgneousMineralz/Quartz.htmlColor may not help to identify mineralhttp://minerals.caltech.edu/Silica_Polymorphs/index.htmlhttp://www.palagems.com/mineral_news_2008_v1.htmhttp://khubert.blogspot.com/2006/01/pink-halite.htmlhttp://www.statesymbolsusa.org/Colorado/mineral_Rhodochrosite.htmlColor may be diagnostichttp://geology.csupomona.edu/alert/mineral/color.htmCopper Nonsilicate—bornite copper oreIMPORTANT MINERAL PROPERTIES• HARDNESS: compare to common items• CLEAVAGE: planes of internal weakness• FRACTURE• SPECIFIC GRAVITY: density, heft• “OTHER” PROPERTIES– MAGNETISM, TASTE, SMELL– FIZZ IN Hydrochloric ACID• DILUTE, HEATED, IF MINERAL IS POWDERED– DOUBLE REFRACTIONFingernail 2.5Hardness1. Talc2. Gypsum3. Calcite4. Fluorite5. Apatite6. Orthoclase7. Quartz8. Topaz9. Corundum10. Diamond Penny 3.5Steel nail 5Glass 5.5Streak plate 7.5Conchoidal fracture—quartz Cleavage—muscovite5Potassium Feldsparhttp://www.pitt.edu/~cejones/GeoImages/1Minerals/1IgneousMineralz/Feldspars.htmlPlagioclase HornblendeGalena cleavage Halite Calcitehttp://marlimillerphoto.com/Min.htmlFibrous fracture—asbesoformmineralEffervescence Double
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