GEL Mineralogy - Optical Mineralogy

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1 Disclaimer: These reviews are courtesy of the instructor. While care has been taken to include everything that might be tested, omissions or oversights may have occurred. The instructor shall NOT be liable for any missed answer on your part just because the topic is not explicitly mentioned. It is still the STUDENT S RESPONSIBILITY to know and be able to use concepts addressed during lectures, labs, or required texts. Mineralogy Exam Review Sheet: (Things I need to know...) BOLD = Minerals you must be able to identify WITHOUT the aid of written material Normal = Minerals you should be able to identify WITH the aid of written material. Important: You must know mineral name, chemical formula, crystal structure and mineral group for each. Anatase (= Octahedrite) TiO 2 Tetragonal Oxide Andalusite Al 2 SiO 5 Orthorhombic Anhydrite CaSO 4 Orthorhombic Sulfate Apatite Ca 5 (F 3 Cl)(PO 4 ) 3 Hexagonal Phosphate Arsenopyrite FeAsS Orthorhombic Sulphide Augite (Pyroxene) Ca(Mg, Fe, Al)(Al,Si) 2 O 6 Monoclinic Inosilicate Azurite Cu 3 (CO 3 ) 2 (OH) 2 Monoclinic Carbonate Barite BaSO 4 Orthorhombic Sulfate Bauxite Al 2 O 3 * 2H 2 O None Oxide (Mixture) Beryl Be 3 Al 2 Si 6 O 18 Hexagonal Cyclosilicate Biotite (Mica) K(Mg,Fe) 3 AlSi 3 O 10 (OH) 2 Monoclinic (small angle) Phyllosilicate Bornite Cu 5 FeS 4 Isometric Sulphide Brookite TiO 2 Orthorhombic Oxide Calcite CaCO 3 Hexagonal- Carbonate Chalcopyrite CuFeS 2 Tetragonal Sulphide Chlorite (MgFe) 5 Al 2 Si 3 O 10 (OH) 8 Monoclinic Phyllosilicate Chromite Fe 2 Cr 2 O 4 Isometric Oxide

2 Cinnabar HgS Hexagonal- Sulphide Copper Cu Isometric Native Mineral Cordierite (Mg, Fe) 2 Al 4 Si 5 O 18 Orthorhombic Cyclosilicate Corundum Al 2 O 3 Hexagonal Oxide Dolomite CaMg(CO 3 ) 2 Hexagonal- Carbonate Epidote Ca 2 (Al,Fe) 3 (SiO 4 ) 3 OH Monoclinic Sorosilicate Fluorite CaF 2 Isometric Halide Galena PbS Isometric Sulphide Garnet Group X 3 Y 2 (SiO 4 ) 3 X: divalent metals (Ca, Fe, Mg, &/or Mn) Y: trivalent metals (Al, Cr, Fe, &/or Mn) Isometric Graphite C Hexagonal- Native Mineral Gypsum CaSO 4 *2H 2 O Monoclinic Sulfate Halite NaCl Isometric Halide Hematite Fe 2 O 3 Hexagonal- Oxide Hornblende (Amphibole) Ca 2 Na(Mg,Fe) 4 (Al, Fe,Ti) 3 Si 6 O 22 (O,OH) 2 Monoclinic Inosilicate Ilmenite FeTiO 3 Hexagonal Oxide Kaolinite (Clay) Al 2 Si 2 O 5 (OH) 4 Monoclinic Phyllosilicate Kyanite Al 2 SiO 5 Triclinic Limonite FeO(OH)*nH 2 O None Oxide Magnetite Fe 3 O 4 Isometric Oxide Malachite Cu 2 CO 3 (OH) 2 Monoclinic Carbonate Microcline KAlSi 3 O 8 Triclinic Tectosilicate Molybdenite MoS 2 Hexagonal Sulphide Muscovite (Mica) KAl 3 Si 3 O 10 (OH) 2 Monoclinic Phyllosilicate

3 Octahedrite (= Anatase) TiO 2 Tetragonal Oxide Olivine Fosterite Fayalite (Mg,Fe)SiO 4 MgSiO 4 FeSiO 4 Orthorhombic Orthoclase KAlSi 3 O 8 Monoclinic Tectosilicate Orpiment As 2 S 3 Monoclinic Sulphide Plagioclase Albite Labradorite Anorthite NaAlSi 3 O 8 solid solution series CaAl 2 Si 2 O 8 Triclinic Tectosilicate Pyrite FeS 2 Isometric Sulphide Pyrolusite MnO 2 Tetragonal Oxide Quartz SiO 2 Hexagonal Tectosilicate Realgar AsS Monoclinic Sulphide Rutile TiO 2 Tetragonal Oxide Sillimanite Al 2 SiO 5 Orthorhombic Sphalerite ZnS (may contain Fe, Mn, Cd) Isometric Sulphide Sphene / Titanite CaTiSiO 5 Monoclinic Staurolite FeAl 4 Si 2 O 10 (OH) 2 Pseudo- Orthorhombic Stibnite Sb 2 S 3 Orthorhombic Sulphide Sulphur S Orthorhombic Native Mineral Sylvite KCl Isometric Halide Talc Mg 3 Si 4 O 10 (OH) 2 Monoclinic Phyllosilicate Topaz Al 2 SiO 4 (F,OH) Orthorhombic Tourmaline Na(Mg,Fe,Li,Al,Mn) 3 Al 6 (BO 3 ) 3 (Si 6 O 18 )(OH,F) 4 Hexagonal Cyclosilicate Zircon ZrSiO 4 Tetragonal

4 Additional Requirements: 1. Be able to give names and conditions of formation for the various SiO 2 isomorphs. 2. Be able to solve for oxide formulas of minerals or to combine oxide formulas of minerals into mineral sum formulas a. Example: A oxide composition of K 2 O * Al 2 O 3 * 6SiO 2 would best approximate which of the following minerals? b. Example: If you took exactly 120.2g SiO 2 powder, 102.0g Al 2 O 3 powder and 62.0g Na 2 O powder, mixed it all together and melted it in a crucible, which of the following minerals would most likely form? 3. Be able to differentiate between dioctahedral & trioctahedral phyllosilicates from chemical formulas and some hand samples. Remember Brucite & Gibbsite! 4. Be able to identify Neso-, Soro-, Ino (Single Chain) -, Ino (Double Chain)-, Cyclo-, Phyllo-, and Tectosilicates from their chemical formulas. In order to do so you may want to complete the table below: Cyclosilicate Sorosilicate -Si 2 O 7 group Phyllosilicate Inosilicate (single) Inosilicate (double) Tectosilicate 5. In addition to the above minerals, know the chemical composition, crystal class, layering and mineral group for the following minerals: (a) Montmorillonite, (b) Pyrophyllite, (c) Vermiculite, (d) Crysotile, (e) Smectite 6. Know Bowen s Reaction Series backwards and forwards and associated oxide formulas. 7. Be able to make inferences about mineral occurring together a. Example: You find the mineral leucite in a rock. A greenish-black mineral with a hardness 5-6 and good prismatic cleavage is also present. This greenish-black mineral is most likely...? 8. Know MOHS hardness scale backwards and forwards! 9. Be able to accurately test for mineral density using your digital electronic scales and the single pan hydrostatic method as well as the pycnometer method. Hint: Do NOT forget to calibrate you electronic scales before and sometimes during use!!! 10. Be able to identify cleavage types from pictures and specimens.

5 MINERAL EXAM OVERVIEW Section 1 - Multiple Choice (40 pts ) 40 points (40 questions - 1pt ea.) Questions 1-10 will be power point projection. Many are moving images. Each projected question will last less than 1 minute. Slides will be shown only once, so be on time and pay attention. Questions are multiple choice questions. Some, however, will require lab tests to be performed. Example: Obtain Mineral Sample #1 from the instructor and test for hardness. Which of the following answers most closely describes the hardness of the mineral? Note: Minerals may contain impurities or may be chemically altered. Always look for fresh samples and do several test. a b c d e. > 5.5 Section 2 - Mineral ID without written material (bolded minerals listed above)... Must know chemical formula, crystal system, correct mineral group 4 Minerals (10 pts ea.) Mineral Name (4) Chemical Formula (3) Crystal System (2) (1) Section 3-2 Minerals Take home Mineral ID of unknowns. Other minerals in list above. (10 pts ea.) Exact Mineral Name (3 pts): Density (3pts): 40 points 20 points Mohs Hardness (2pts): Other Applicable Observations / Tests (2pt):