Minerals

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Minerals

  1. 1. Minerals
  2. 2. What is a Mineral? <ul><li>Naturally Occurring </li></ul><ul><li>Inorganic </li></ul><ul><li>Solid </li></ul><ul><li>Definite Chemical Formula </li></ul><ul><li>Definite Crystal Structure </li></ul>
  3. 3. Naturally Occurring <ul><li>Formed by natural processes not in the laboratory. </li></ul><ul><ul><li>Is an ice cube a mineral? </li></ul></ul><ul><ul><li>Is the ice on the windshield of a car a mineral? </li></ul></ul><ul><ul><li>Minerals manufactured by humans are not considered minerals. </li></ul></ul>
  4. 4. Inorganic <ul><li>Formed by inorganic processes; not living </li></ul><ul><li>Minerals are not made from living things. </li></ul><ul><li>Coal is made of carbon. Is it a mineral? </li></ul>
  5. 5. Solid <ul><li>Minerals cannot be a gas or a liquid. </li></ul>- H 2 O as ice in a glacier is a mineral, but water is not.
  6. 6. Definite Crystal Structure <ul><li>Highly ordered atomic arrangement of atoms in regular geometric patterns </li></ul>Apatite Feldspar Diamond Quartz <ul><li>Minerals are crystals with a repeated inner structure. </li></ul>
  7. 8. Definite Chemical Formula <ul><li>Minerals are expressed by a specific chemical formula. </li></ul><ul><li>Gold (Au) </li></ul><ul><li>Calcite (CaCO 3 ) </li></ul><ul><li>Quartz (SiO 2 ) </li></ul><ul><li>Pyrite (FeS 2 ) </li></ul><ul><li>Minerals made of only one type of atom (element) are called native elements. </li></ul><ul><ul><li>Gold </li></ul></ul><ul><ul><li>Copper </li></ul></ul><ul><ul><li>Silver </li></ul></ul>
  8. 9. Types of minerals <ul><li>Minerals are most commonly classified by chemical composition. </li></ul><ul><li>The 2 main groups are silicates and nonsilicates. </li></ul>
  9. 10. Silicates <ul><li>Minerals containing a combination of silicon (Si) and oxygen (O) (most common elements in the earth’s crust) </li></ul><ul><li>Silicate minerals comprise about 90% of the Earth’s crust. </li></ul><ul><li>Silicates minerals often contain other elements such as aluminum, iron, magnesium, and potassium. </li></ul><ul><li>Granite is a rock comprised of the minerals feldspar, biotite mica and quartz. </li></ul>
  10. 11. Feldspar <ul><li>Feldspar minerals make up half of the Earth’s crust and is the main component of most of the rocks found on the Earth’s surface. </li></ul>Feldspar <ul><li>Feldspar contains Si, O, Al, K, Na, and Ca </li></ul>
  11. 12. Biotite Mica <ul><li>soft and shiny minerals that separate easily into sheets </li></ul><ul><li>biotite is one variety of mica </li></ul>
  12. 13. Quartz <ul><li>silicon dioxide ( SiO 2 ) </li></ul><ul><li>is the basic building block of many rocks </li></ul>
  13. 14. Nonsilicates <ul><li>minerals that do not contain the combination of Si and O </li></ul><ul><li>some of these minerals are made up of C, O, F, and S </li></ul>
  14. 15. Classes of nonsilicates <ul><li>Native Elements </li></ul><ul><li>Carbonates </li></ul><ul><li>Halides </li></ul><ul><li>Oxides </li></ul><ul><li>Sulfates </li></ul><ul><li>Sulfides </li></ul>
  15. 16. Native Elements <ul><li>Native elements are composed of only 1 element </li></ul><ul><li>About 20 exist including Au, Pt, C, Cu, S and Ag </li></ul>
  16. 17. Carbonates <ul><li>contain the combinations of carbon and Oxygen in their chemical structure </li></ul><ul><li>calcite (CaCO 3 ) is an example </li></ul><ul><li>carbonates are used in cement, building stones and fireworks </li></ul>
  17. 18. Halides <ul><li>form when atoms containing fluorine, chlorine, iodine, or bromine (halogens) combine with potassium or calcium </li></ul><ul><li>Halite (NaCl) is better known as rock salt </li></ul><ul><li>Fluorite can have many different colors </li></ul><ul><li>Halides are often used in making fertilizers </li></ul>Fluorite
  18. 19. Oxides <ul><li>compounds formed when elements like aluminum or iron bond with oxygen </li></ul><ul><li>Corundum (Al 2 O 3 ) and Magnetite (Fe 3 O 4 ) are important oxides </li></ul><ul><li>Are used in abrasives and airplane parts </li></ul>
  19. 20. Sulfates <ul><li>minerals containing sulfur and oxygen (SO 4 ) </li></ul><ul><li>gypsum (CaSO 4 * 2H 2 O) is a common example </li></ul><ul><li>makes the white sand at White Sands National Monument in NM </li></ul><ul><li>sulfates are commonly used in cosmetics, toothpaste and paints </li></ul>Gypsum
  20. 21. Sulfides <ul><li>minerals containing one or more elements such as lead, iron, or nickel combines with sulfur </li></ul><ul><li>Galena (PbS) is a sulfide </li></ul><ul><li>Sulfides are used to make batteries, medicines and electronic parts </li></ul>Galena
  21. 22. Composition of the Earth’s Crust <ul><ul><li>- Oxygen (O) </li></ul></ul><ul><ul><li>- Silicon (Si) </li></ul></ul><ul><ul><li>- Aluminum (Al) </li></ul></ul><ul><ul><li>- Iron (Fe) </li></ul></ul><ul><ul><li>- Calcium (Ca) </li></ul></ul><ul><ul><li>- Sodium (Na) </li></ul></ul><ul><ul><li>- Potassium (K) </li></ul></ul><ul><ul><li>- Magnesium (Mg) </li></ul></ul><ul><ul><li>Eight Elements that make up over 98% of Earth’s Crust </li></ul></ul>
  22. 23. Where Do Minerals Come From? Magma Evaporation In general, minerals form in two ways: Cooling magma - Crystallization of melted materials From solution - Crystallization of materials dissolved in water At the surface Beneath the surface
  23. 24. Magma <ul><li>Magma is molten material from the mantle that hardens to form rock. </li></ul><ul><li>Lava is magma that reaches the surface. </li></ul><ul><li>Minerals form as hot magma cools inside the crust, or as lava hardens on the surface. </li></ul><ul><li>When these liquids cool to the solid state, they form crystals. </li></ul>
  24. 25. Size of Crystals <ul><li>Magma closer to the surface cools much faster, producing smaller crystals. </li></ul><ul><li>Slow cooling leads to the formation of large crystals. </li></ul><ul><li>When magma remains deep below the surface, it cools slowly over many thousands of years. </li></ul><ul><ul><li>The chemical composition of the magma </li></ul></ul><ul><ul><li>The amount of gas the magma contains </li></ul></ul><ul><ul><li>The rate at which the magma cools </li></ul></ul><ul><li>Depends of several factors: </li></ul>
  25. 26. Minerals from Hot Water Solutions <ul><li>This can happen on the ocean floor when ocean water seeps down through cracks in the crust. </li></ul><ul><li>When a hot water solution begins to cool, the elements and compounds leave the solution and crystallize as minerals. </li></ul><ul><li>A solution is a mixture in which one substance dissolves in another. </li></ul><ul><li>Sometimes, the elements that form a mineral dissolve in hot water and form a solution. </li></ul>
  26. 27. Minerals formed by Evaporation <ul><ul><li>Gypsum </li></ul></ul><ul><ul><li>Calcite crystals </li></ul></ul><ul><ul><li>Minerals containing potassium </li></ul></ul><ul><li>Several other useful minerals also from by the evaporation of seawater: </li></ul><ul><li>Minerals can also form when solutions evaporate. Example: salt from sea water </li></ul>
  27. 28. Minerals formed by Metamorphism <ul><li>When rocks are put under extreme heat and pressure, the chemical composition of the rock can change, forming new minerals. </li></ul><ul><li>Examples: calcite, garnet, graphite, hematite, magnetite, mica and talc. </li></ul>
  28. 29. How Are Minerals Identified? <ul><li>Color </li></ul><ul><li>Luster </li></ul><ul><li>Hardness </li></ul><ul><li>Streak </li></ul><ul><li>Density </li></ul><ul><li>Crystal Shape </li></ul><ul><li>Cleavage and Fracture </li></ul><ul><li>Special Properties </li></ul>
  29. 30. Color <ul><li>Usually the first and most easily observed </li></ul>- Some minerals are the same color as others - Some minerals can have many colors <ul><li>Not a reliable way to identify a mineral </li></ul>QUARTZ ROSE QUARTZ SMOKY QUARTZ
  30. 31. Luster <ul><li>General appearance of a mineral surface in reflected light </li></ul>Glassy- Obsidian
  31. 32. Examples of luster <ul><li>Metallic </li></ul><ul><li>Greasy: resembles the way petroleum jelly or a greasy surface reflects light </li></ul><ul><li>Silky: resembles the way silk reflects light </li></ul><ul><li>Earthy: dull, may be rough or dusty </li></ul><ul><li>Waxy </li></ul><ul><li>Adamantine: resembles the way a diamond shines </li></ul><ul><li>Vitreous: similar to glass </li></ul><ul><li>Resinous: resembles the way plastic reflects light </li></ul><ul><li>Pearly: resembles the way pearls shine </li></ul><ul><li>Pitchy – looks like tar </li></ul><ul><li>Fibrous – looks like fibers </li></ul>
  32. 33. Hardness <ul><li>Resistance to scratching by different items; “scratchability” </li></ul><ul><li>Mohs Hardness Scale is used to determine the hardness of minerals by comparing them to substances of known hardness: </li></ul><ul><ul><li>< 2 fingernail </li></ul></ul><ul><ul><li>3 penny </li></ul></ul><ul><ul><li>~ 5 Steel of a pocket knife </li></ul></ul><ul><ul><li>5.5 Window Glass </li></ul></ul><ul><ul><li>6.6 Steel of a file </li></ul></ul><ul><ul><li>7 Quartz crystal </li></ul></ul>
  33. 34. Mohs Mineral Hardness Scale <ul><li>1) Talc </li></ul><ul><li>2) Gypsum </li></ul><ul><li>3) Calcite </li></ul><ul><li>4) Flourite </li></ul><ul><li>5) Apatite </li></ul><ul><li>6) Feldspar </li></ul><ul><li>7) Quartz </li></ul><ul><li>8) Topaz </li></ul><ul><li>9) Corundum </li></ul><ul><li>10) Diamond </li></ul>Softest Hardest 1 2 3 4 5 6 7 8 9 10
  34. 35. Streak <ul><li>The color of a finely powdered mineral </li></ul><ul><li>Determined by rubbing the mineral on a piece of unglazed porcelain (streak plate) </li></ul>
  35. 36. Density <ul><li>The amount of matter in a given space </li></ul><ul><li>Specific Gravity is the comparison of a substance’s density to the density of water </li></ul>
  36. 37. Crystal Shape <ul><li>Minerals have a characteristic crystal shape resulting from the atomic packing of the atoms when the mineral is forming </li></ul>
  37. 38. Cleavage and Fracture <ul><li>Cleavage is the tendency of a mineral to split or crack along parallel or flat planes </li></ul><ul><li>Fracture occurs when a mineral breaks at random lines instead of at consistent cleavage planes. </li></ul>Obsidian No Cleavage 1 Direction of Cleavage Conchoidal Fracture BIOTITE QUARTZ
  38. 39. Fracture
  39. 40. Special Properties <ul><li>Magnetism (Magnetite) </li></ul><ul><li>Taste (Halite) </li></ul><ul><li>Smell (Sulfur) </li></ul><ul><li>Reaction to HCl (Calcite) </li></ul><ul><li>Double refractive - a thin, clear piece of calcite placed over an image will cause a double image </li></ul><ul><li>Radioactivity - minerals containing radium or uranium can be detected by a Geiger counter </li></ul><ul><li>Glowing under ultraviolet light (Fluorite) </li></ul>
  40. 41. Economic Importance of Minerals <ul><li>Minerals are in many things we see and use everyday such as; bricks, glass, cement, plaster, iron, gold </li></ul>
  41. 42. Every American Requires 40,000 Pounds of New Minerals per Year <ul><li>at this level of consumption the average newborn infant will need a lifetime supply of: </li></ul><ul><li>-795 lbs of lead (car batteries, electric components) </li></ul><ul><li>-757 lbs of zinc (to make brass, rubber, paints) </li></ul><ul><li>-1500lbs of copper (electrical motors, wirings </li></ul><ul><li>-3593 lbs aluminum (soda cans, aircraft) </li></ul><ul><li>-32,700 lbs of iron (kitchen utensils, automobiles, buildings) </li></ul><ul><li>-28,213 lbs of salt (cooking, detergents) </li></ul><ul><li>-1,238,101 lbs of stone, sand, gravel, cement (roads, homes, etc.) </li></ul>

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