Rocks & minerals


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Rocks & minerals

  1. 1. Unit 4 Lithosphere • Rocks & Minerals
  2. 2. OK – so here’s the real introduction to Rocks & Minerals
  3. 3. Minerals can be identified by their chemical and physical properties.
  4. 4. Minerals Fist List igh H ! ve! Fi What is a Mineral?
  5. 5. Minerals
  6. 6. What does that mean?!?!?! --Not a gas or a liquid --Has a definite shape and volume QUESTION? Is oil a mineral?? Answer… No, because it is a liquid. So lid ,E ar th Ma ter ial
  7. 7. ccurring --Not man-made ly O Natural What does that mean?!?!?!
  8. 8. --Not formed from living things or the remains of living things Inorgan ic What does that mean?!?!?! --NON-LIVING!! EXAMPLES 1. Coal is NOT a mineral because it comes from plants. 2. Amber is NOT a mineral because it comes from tree sap. 3. A pearl is NOT a mineral because it comes from oysters.
  9. 9. -Gold (Au) -Pyrite (FeS²) -Graphite (C) -Diamond (C) lF Ch em ica --Chemical formula can be found on page 16 of ESRT. EXAMPLES De fin ite --The elements that make up the minerals are combined in definite proportions orm ula What does that mean?!?!?!
  10. 10. What does that mean?!?!?! --Atoms are arranged in a repeating pattern --Each mineral has a different INTERNAL ARRANGEMENT OF ATOMS that gives it distinct physical and chemical properties it e fin De r C st y lS a uc tr re tu
  11. 11. What does that mean?!?!?! QUESTION How does the mineral graphite, which is soft have the same chemical formula as diamond, which is the hardest mineral in the world? ANSWER Because their internal arrangement of atoms are different ite fin e D ry C re tu uc tr lS ta s
  12. 12. How are Minerals Identified?? Fill in the spiders legs as we go!!
  13. 13. Minerals can be identified by their chemical and physical properties.
  14. 14. How are Minerals Identified?? --Least useful for identification --One mineral can come in many colors EXAMPLE: --Hematite: Comes in black, red and brown Co lo r
  15. 15. How are Minerals Identified?? 1. Some minerals are always the same color Sulfur 2. Some minerals can have many colors Smoky Quartz Rose Quartz Quartz
  16. 16. Colors can vary as a result of… A. Chemical Impurities– Cobalt compounds tend to be pink, purple, or blue Manganese—tends to produce pink colors
  17. 17. Colors can vary as a result of… B. Oxidation—exposure to air and water changing the color of the mineral. Ex. Rust --Iron is the dominant coloring agent in rocks and soils
  18. 18. How are Minerals Identified?? --the color of a mineral when it is finely powdered --determined by rubbing the mineral on a piece of tile Hematite has a reddish-brown streak. St rea k
  19. 19. How are Minerals Identified?? --describes how a mineral appears to reflect light Lus t There are 2 categories in which a minerals luster can fall… Metallic OR er Non-Metallic
  20. 20. How are Minerals Identified?? A. Metallic– reflects light like metal (shiny) Graphite Galena Pyrite
  21. 21. How are Minerals Identified?? B. Non-Metallic—any mineral which DOES NOT exhibit shiny metallic characteristics Ex. Quartz
  22. 22. Metallic or Non-Metallic?? Non-Metallic Mica Pearly luster Metallic Magnetite
  23. 23. Metallic or Non-Metallic?? Non-Metallic Pyroxene Dull luster
  24. 24. How are Minerals Identified?? --Resistance of a mineral to being scratched --Moh’s Hardness Scale —compares the hardness of the mineral to 10 reference minerals. Hardness
  25. 25. How is Hardness Determined?? Softest Hardest The scale consists of number 1 through 10; 1 being the softest and 10 being the hardest. Each number represents a different mineraleach harder than the previous. The 10 minerals are to the left.
  26. 26. How is Hardness Determined?? Several common household items have a fixed hardness, and can be used to test for hardness. -Fingernail = 2.5 -Copper penny = 3-3.5 -Nail = 4.5 -Knife blade = 5.5 -Glass = 5.5 -Steel file = 6.5 -Streak plate = 7
  27. 27. What Determines Hardness? --Hardness is determined by a minerals internal arrangement of atoms. Ex. Diamond vs. Graphite -Diamond has hardness of 10 and graphite is ranked between 1 and 2. Diamond is about 40 times harder than graphite due to the way the atoms are arranged. --Hardness is the best property to use to identify a mineral.
  28. 28. How are Minerals Identified?? e or vag Clea re ractu F Cleavage—when a mineral breaks along a flat, smooth surface
  29. 29. Examples of Minerals that show Cleavage Mica exhibits basal cleavage. Galena exhibits cubic cleavage.
  30. 30. What Determines Cleavage and Hardness? A minerals internal arrangement of atoms!!
  31. 31. How are Minerals Identified?? Fracture—When a mineral breaks along irregular rough surfaces. e or vag Clea ure act Fr EX. Quartz
  32. 32. How are Minerals Identified?? --The amount of matter in a given space (mass/volume) r Heft nsity o De Depends on… -kind of atoms which make up the mineral -how the atoms are arranged in the crystal lattice
  33. 33. How are Minerals Identified?? Crystal Shape --Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the mineral is forming
  34. 34. How are Minerals Identified?? -Magnetism (Magnetite) -Glowing under ultraviolet light (Fluorite) -Salty taste (Halite) -Smell (Sulfur) Spe cial Pr ope rtie s -Reaction to HCl (Calcite)
  35. 35. Rocks Parent Material for all Rock?? Magma!!
  36. 36. Lithosphere
  37. 37. How are rocks formed? Rocks are classified by their process of formation.
  38. 38. The Rock Cycle Igneous Rocks • The Rock Cycle describes the continually changing structure of rocks. Magma Metamorphic Rocks Sediments Sedimentary Rocks
  39. 39. Texture and Grain Size • Texture is described based on grain size, grain shape, and grain pattern. • Most rocks are made up of tiny particles of minerals or other rocks, which are called grains. • A rock’s grains give it its texture
  40. 40. Distribution of Rocks in the U.S.
  41. 41. Rocks  Made of two or more different minerals that have been: • cemented together (Sedimentary) • squeezed and heated together (Metamorphic) • melted and cooled together (Igneous)
  42. 42. ROCKS Sedimentary Metamorphic Igneous sediments and minerals are compacted and cemented With dissolved minerals Clastic – pieces of other rocks Cemented into rock Chemical – Evaporites From seawater Organic/Bioclastic Remains of plants Or animals which Are transformed Into rock
  43. 43. Igneous Rock • Igneous rock forms when magma or lava COOLS Solidifies Crystallizes hardens
  44. 44. Crystallization
  45. 45. TEXTURE Intrusive or Plutonic Extrusive or Volcanic Coarse Grained large crystals Non-Vesicular (no gas bubbles) Fine Grained (small crystals) Glassy Gas Pockets (vesicular) Magma LAVA Underground Above ground Slow cooling FAST cooling
  46. 46. Granite vs. Obsidian Extrusive Intrusive
  47. 47. Igneous Rock Mineral Composition Light Colored Dark Colored Rocks Called Rocks Called FELSIC MAFIC Low density High Density Rich in Aluminum Rich in IRON & Magnesium
  48. 48. Sedimentary Rocks Form when SEDIMENTS And Minerals Are cemented together The 3 types of sedimentary rock are Clastic Chemical Organic
  49. 49. Origins of Sedimentary Rock – Draw an arrow from “CLASTIC” •Through the process of weathering , rock is loosened and carried away with wind and water by As the layers stack up, they become heavier until the weight squeezes the layers together during compaction . erosion . The sediment then settles out of the wind and water during deposition. The deposition sediment begins to settle out and form layers . Dissolved minerals act as glue in a process known as . Cementation
  50. 50. • This is a sample of sandstone, a sedimentary rock that formed from sand grains.
  51. 51. Chemical • Formed when minerals dissolved in water, precipitate out and form crystals on the sea floor – Includes evaporites.
  52. 52. Organic (bioclastic) – rocks formed from the remains of plants and/or animals that undergoes a transformation into rock.
  53. 53. • This is a sample of limestone, a sedimentary rock made of calcium carbonate that formed under water indirectly from the remains of tiny marine organisms.
  54. 54. Grand Canyon
  55. 55. Metamorphic Rocks Conditions that cause rocks to : undergo metamorphism include • Deep burial and pressure or hot contact zones • Metamorphic rocks are often found in mountainous regions You’ll have to add this to your notes on page 8
  56. 56. Metamorphic Rocks – formed when a rock is changed by Heat Pressure Chemical due to Contact Metamorphic rocks are characterized by: • Increased DENSITY • NEW Minerals • BANDING
  57. 57. Metamorphic Rocks are classified by the arrangement of their: MINERALS
  58. 58. Into two types of metamorphic rocks called: Foliated Where the minerals grains are Squeezed and curved or folded and Non Foliated Where the minerals grains are Not aligned and appear MASSIVE
  59. 59. Foliated (think FOLD) Mica Schist Increased HEAT and PRESSURE Gneiss
  60. 60. Non-Foliated • Massive Metamorphic rocks
  61. 61. Metamorphic Rock Chart
  62. 62. • Increasing metamorphic change occurs with increasing temperatures and pressures. • If the melting point is reached, the change is no longer metamorphic, and igneous rocks are formed AGAIN.