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Rock exam ese 11


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Rock exam ese 11

  1. 1. 1. Microcline(K-Feldspar) • Microcline(K-Feldspar)
  2. 2. • Microcline (KAlSi3O8) is an important igneous rock-forming tectosilicate mineral. It is a potassium-rich alkali feldspar.
  3. 3. 2. Milky quartz sample
  4. 4. 2. Milky quartz sample Crystal habit 6-sided prism ending in 6-sided pyramid (typical), drusy, fine- grained to microcrystalline, massive Crystal system α-quartz: trigonal trapezohedral class 3 2; β-quartz: hexagonal62
  5. 5. 3. Biotite
  6. 6. 3. Biotite • . Biotite was named by J.F.L. Hausmann in 1847 in honour of the French physicist Jean- Baptiste Biot, who, in 1816, researched the optical properties of mica, discovering many unique properties
  7. 7. 3. Biotite • Biotite is a sheet silicate. Iron, magnesium, aluminium, silicon, oxygen, and hydrogen form sheets that are weakly bound together by potassium ions. It is sometimes called "iron mica" because it is more iron-rich than phlogopite. It is also sometimes called "black mica" as opposed to "white mica" (muscovite
  8. 8. 4. muscovite
  9. 9. 5. Albite (plagioclase feldspar)
  10. 10. 5. Albite (plagioclase feldspar)
  11. 11. 6. Hornblende (amphibole)
  12. 12. 6. Hornblende (amphibole) • containing ions of iron and/ormagnesium in their structures. Amphiboles can be green, black, colorless, white, yellow, blue, or brownAmphiboles crystallize into two crystal systems, monoclinic and orthorhombic. In chemical composition and general characteristics they are similar to the pyroxenes
  13. 13. 6. Hornblende (amphibole) • Most apparent, in hand specimens, is that amphiboles form oblique cleavage planes (at around 120 degrees), whereas pyroxenes have cleavage angles of approximately 90 degrees. Amphiboles are also specifically less dense than the corresponding pyroxenes.
  14. 14. 7. Augite (pyroxene)
  15. 15. 7. Augite (pyroxene) • Augite is a common rock forming single chain inosilicate mineral with formula (Ca,Na)(Mg,Fe,Al,Ti)(Si,Al)2O6. The crystals are monoclinic and prismatic. Augite has two prominent cleavages, meeting at angles near 90 degree
  16. 16. 8. Olivine • Olivine occurs in both mafic and ultramafic igneous rocks and as a primary mineral in certain metamorphic rocks. Mg-rich olivine crystallizes from magma that is rich in magnesium and low in silica. • That magma crystallizes to mafic rocks such asgabbro and basalt
  17. 17. 8. Olivine
  18. 18. 9. Kaolinite
  19. 19. 9. Kaolinite
  20. 20. 9. Kaolinite • group of industrial minerals, with the chemical composition Al2Si2O5(OH)4. It is a layered silicate mineral, with one tetrahedral sheet linked through oxygen atoms to one octahedral sheet of alumina octahedra.Rocks that are rich in kaolinite are known as kaolin or china clay. • The name is derived from Chinese Kao-Ling
  21. 21. 10. Calcite
  22. 22. 10. Calcite • Calcite is a carbonate mineral and the most stable polymorph of calcium carbonate(CaCO3). The other polymorphs are the minerals aragonite and vaterite. Aragonite will change to calcite at 380–470°C,[5] and vaterite is even less stable
  23. 23. 10. Calcite crystals • Calcite crystals are trigonal- rhombohedral, though actual calcite rhombohedra are rare as natural crystals. • . It may occur as fibrous, granular, lamellar, or compact. Cleavage is usually in three directions parallel to the rhombohedron form. Its fracture is conchoidal, but difficult to obtain.
  24. 24. 10. Calcite crystals • It has a defining Mohs hardness of 3, a specific gravity of 2.71, and its luster is vitreous in crystallized varieties. Color is white or none, though shades of gray, red, orange, yellow, green, blue, violet, brow n, or even black can occur when the mineral is charged with impurities. • Calcite is transparent to opaque and may occasionally show phosphorescence orfluorescence
  25. 25. 11. Dolomite
  26. 26. 11. Dolomite • Dolomite is a carbonate mineral composed of calcium magnesiumcarbonate CaMg(CO3)2. • Dolomite is also used to describe the sedimentary carbonate rock dolostone which is composed predominantly of the mineral dolomite. Limestone which contains smaller amounts of the mineral dolomite is referred to as dolomitic limestone, or in the older literature magnesian limeston
  27. 27. 12. Bauxite • Bauxite is an aluminium ore and is the main source of aluminium. This form of rock consists mostly of the minerals gibbsite Al(OH)3, boehmite γ- AlO(OH), and diaspore α-AlO(OH), in a mixture with the two iron oxides goethite and haematite, the clay mineralkaolinite, and small amounts of anatase TiO2. Bauxite was named after the village Les Baux in southern France, where it was first recognised as containing aluminium and named by the French geologist Pierre Berthier in 1821
  28. 28. 13. Talc • (derived from Persian: tālk; Arabic: talk) is a mineral composed of hydrated • magnesium silicate with the chemical formula H2Mg3(SiO3)4 or Mg3Si4O10(OH)2. In loose form, it is the widely used substance known as talcum powder. It has a perfect basal cleavage, and the folia are non-elastic, although slightly flexible. It is the softest known mineral and listed as 1 on the Mohs hardness scale
  29. 29. 13. Talc • It can be easily scratched by a fingernail. It is also sectile (can be cut with a knife). It has a specific gravity of 2.5–2.8, a clear or dusty luster, and is translucent to opaque. Talc is not soluble in water, but it is slightly soluble in dilute mineral acids. Its colour ranges from white to grey or green and it has a distinctly greasy feel. Its streak is white
  30. 30. 13. Talc • Talc is a metamorphic mineral resulting from the metamorphism of magnesian minerals such as serpentine, pyroxene, amphibole, • olivine
  31. 31. 14. Garnets • Garnets possess similar physical properties and crystal forms but different chemical compositions. The different species are pyrope, almandine, spessartine, grossular( varieties of which are hessonite or cinnamon- stone and tsavorite), uvarovite andandradite. The garnets make up two solid solution series: pyrope-almandine-spessarite and uvarovite- grossular-andradite
  32. 32. 14. Garnets
  33. 33. Magnetics used in garnet series identification • For gem identification purposes, a pick-up response to a strong neodymium magnet separates garnet from all other natural transparent gemstones commonly used in the jewelry trade.
  34. 34. Magnetics used in garnet series identification • Magnetic susceptibility measurements in conjunction with refractive index can be used to distinguish garnet species and varieties, and determine the composition of garnets in terms of percentages of end-member species within an individual gems
  35. 35. 16. Halite
  36. 36. 16. Halite
  37. 37. 16. Halite
  38. 38. 16. Halite
  39. 39. 17. Gypsum • of calcium sulfate dihydrate, with thechemical formula CaSO4·2H2O.[3] It can be used as a fertilizer, is the main constituent in many forms of plaster and is widely mined. A very fine- grained white or lightly tinted variety of gypsum, called alabaster, has been used for sculpture by many cultures including Ancient Egypt, Mesopotamia and the Nottingham alabasters of medieval England. It is the definition of a hardness of 2
  40. 40. 18. Chalcopyrite • a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black. • On exposure to air, chalcopyrite oxidises to a variety of oxides, hydroxides and sulfates
  41. 41. 18. Chalcopyrite
  42. 42. The unit cell of chalcopyrite. Copper is shown in pink, iron in blue and sulfur in yellow.
  43. 43. zinc blende ZnS (sphalerite • Crystallographically the structure of chalcopyrite is closely related to that of zinc blende ZnS (sphalerite). The unit cell is twice as large, reflecting an alternation of Cu+ and Fe3+ ions replacing Zn2+ ions in adjacent cells. In contrast to the pyritestructure chalcopyrite has single S2- sulfide anions rather than disulfide pairs. Another difference is that the iron cation is not diamagnetic low spin Fe(II) as in pyrite
  44. 44. 19. Galena
  45. 45. Lead Sulfide –Pd(II)S • Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms. It is often associated with the minerals sphalerite, calcite and fluorite
  46. 46. Simple Cubic crystal system Lead Sulfide –Pd(II)S
  47. 47. 20. Limonite • Limonite is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·nH2O, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely. Limonite is one of the two principle iron ores, the other being hematite, and has been mined for the production of iron since at least 2500 BCE
  48. 48. 20. Limonite Limonite: hydrated iron(III) oxide-hydroxides
  49. 49. Fluorite • (also called fluorspar) is a halide mineral composed of calcium fluoride, CaF2. It is an isometric mineral with a cubic habit, though octahedral and more complex isometric forms are not uncommon. • Fluorite is a colorful mineral, both in visible and ultraviolet light, and the stone has ornamental and lapidary uses.
  50. 50. Fluorite • Industrially, fluorite is used as a flux for smelting, and in the production of certain glasses and enamels. The purest grades of fluorite are a source of fluoride for hydrofluoric acid manufacture, which is the intermediate source of most fluorine-containing fine chemicals. Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also usable in the far-ultraviolet range where conventional glasses are too absorbent for us
  51. 51. Fluorite • Optically clear transparent fluorite lenses have low dispersion, so lenses made from it exhibit less chromatic aberration, making them valuable in microscopes and telescopes. Fluorite optics are also usable in the far- ultraviolet range where conventional glasses are too absorbent for us
  52. 52. Fluorite
  53. 53. Fluorite
  54. 54. fluorescence of fluorite • Many samples of fluorite exhibit fluorescence under ultraviolet light, a property that takes its name from fluorite.[ Many minerals, as well as other substances, fluoresce. • Fluorescence involves the elevation of electron energy levels by quanta of ultraviolet light, followed by the progressive falling back of the electrons into their previous energy state, releasing quanta of visible light in the process
  55. 55. fluorescence of fluorite • In fluorite, the visible light emitted is most commonly blue, but red, purple, yellow, green and white also occur. The fluorescence of fluorite may be due to mineral impurities such as yttrium, ytterbium, or organic matter in the crystal lattice
  56. 56. Graphite • allotrope of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω (graphō), "to draw/write", for its use in pencils, where it is commonly called lead (not to be confused with the metallic element lead). Unlike diamond (another carbon allotrope), graphite is an electrical conductor, a semimetal. It is, consequently, useful in such applications as arc lampelectrodes.
  57. 57. Graphite • . Therefore, it is used in thermochemistry as the standard state for defining the heat of formation of carbon compounds. Graphite may be considered the highest grade ofcoal, just above anthracite and alternatively called meta-anthracite, although it is not normally used as fuel because it is difficult to ignite.
  58. 58. Graphite
  59. 59. Graphite
  60. 60. • • Graphite • Hematite • Magnetite (lodestrone) • Sphalerite
  61. 61. Begin lab 4 and lab 5 with faith heart and skill