Minerals

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Minerals

  1. 1. Minerals Nature’s Beautiful Creation
  2. 2. Mineral <ul><li>A naturally occurring, inorganic solid with definite composition and an orderly arrangement of atoms </li></ul><ul><li>There are about 4,000 different minerals found on Earth </li></ul>
  3. 3. Mineral Characteristics <ul><li>All minerals are formed by a natural process </li></ul><ul><li>Minerals are inorganic </li></ul><ul><li>Every mineral is an element or compound with a definite chemical composition </li></ul><ul><li>Minerals are crystalline solids ( crystalline means that atoms are arranged in a pattern that is repeated over and over again) </li></ul>
  4. 4. The Structure of Minerals <ul><li>A crystal is a solid in which the atoms are arranged in orderly, repeating patterns. </li></ul>
  5. 5. Crystal Systems <ul><li>A crystal’s shape depends on how its atoms are arranged. </li></ul><ul><li>Crystal shapes can be organized into groups known as crystal systems </li></ul>
  6. 6. Cubic <ul><li>Minerals are equal in size along all three principal dimensions. </li></ul>
  7. 7. Fluorite
  8. 8. Hexagonal <ul><li>Horizontal distances between the opposite crystal surfaces are equal. These crystal surfaces intersect to form 60 ° or 120° angles. </li></ul><ul><li>The vertical length is longer or shorter than the horizontal lengths. </li></ul>
  9. 9. Aragonite
  10. 10. Tetragonal <ul><li>Tetragonal crystals are much like cubic, except that one of the principal dimensions is longer or shorter than the other two dimensions. </li></ul>
  11. 11. Zircon
  12. 12. Orthorhombic <ul><li>Have dimensions that are unequal in length, resulting in crystals with a brick-like shape. </li></ul>
  13. 13. Barite
  14. 14. Monoclinic <ul><li>Exhibit unequal dimensions in their crystal structure. </li></ul><ul><li>Only one right angle forms where crystal surfaces meet. The other angles are oblique. </li></ul>
  15. 15. Orthoclase
  16. 16. Triclinic <ul><li>Minerals exhibiting the least symmetry. </li></ul><ul><li>They are unequal in all dimensions. </li></ul><ul><li>All angles where crystal surfaces meet are oblique. </li></ul>
  17. 17. Rhodonite
  18. 18. Crystal Formations
  19. 19. Crystals from Magma <ul><li>As magma cools, its atoms lose heat energy, move closer together, and begin to combine into compounds. During the process, atoms of different compounds arrange themselves into orderly, repeating patterns. </li></ul><ul><li>The type and amount of elements present in a magma partly determine which minerals will form. </li></ul><ul><li>The size of the crystals that form depends partly on how rapidly the magma cools. </li></ul>
  20. 20. Crystals from Solution <ul><li>When water evaporates, as in a dry climate, ions that are left behind can come together to form crystals like halite. </li></ul><ul><li>If too much of a substance is dissolved in water, ions can come together and crystals of that substance can begin to form in a solution. </li></ul>
  21. 21. Halite
  22. 22. Mineral Compositions and Groups <ul><li>Ninety elements occur naturally in Earth’s crust. </li></ul><ul><li>Approximately 98% of the crust is made of only 8 of these elements (O, Si, Al, Fe, Ca, Na, K, Mg) </li></ul>
  23. 23. Silicates <ul><li>A group where most of the common rock-forming minerals belong </li></ul><ul><li>Minerals that contain Silicon and Oxygen </li></ul><ul><li>Si and O are the two most abundant elements in Earth’s crust. </li></ul>
  24. 24. Feldspar
  25. 25. Quartz
  26. 26. Carbonate <ul><li>Calcite </li></ul>
  27. 27. Mineral Identification
  28. 28. Physical Properties <ul><li>Mineral Appearance </li></ul><ul><li>Color and appearance are the two obvious clues that can be used to identify minerals. </li></ul><ul><li>Hardness </li></ul><ul><li>A measure of how easily a mineral can be scratched. </li></ul>
  29. 29. Mohs Scale <ul><li>In 1824, the Austrian scientist Friedrich Mohs developed a list of minerals to compare their hardness. </li></ul><ul><li>Hardness of common objects: </li></ul><ul><li>Fingernail – 2.5 </li></ul><ul><li>Piece of copper – 2.5 to 3 </li></ul><ul><li>Iron nail – 4.5 </li></ul><ul><li>Steel file – 6.5 </li></ul><ul><li>Streak plate – 7.0 </li></ul>
  30. 30. Talc – 1 (softest)
  31. 31. Gypsum – 2
  32. 32. Calcite – 3
  33. 33. Fluorite – 4
  34. 34. Apatite – 5
  35. 35. Feldspar – 6
  36. 36. Quartz – 7
  37. 37. Topaz – 8
  38. 38. Corundum – 9
  39. 39. Diamond – 10 (Hardest)
  40. 40. <ul><li>Luster </li></ul><ul><li>The way mineral reflects light. </li></ul><ul><li>a. Metallic Luster – can be compared to the luster of a belt buckle or the shine to metallic cooking utensils. </li></ul><ul><li>b. Nonmetallic Luster – included terms are dull, pearly, silky, and glassy (quartz, calcite, halite, and fluorite). </li></ul><ul><li>Specific Gravity </li></ul><ul><li>The ratio of a mineral’s weight compared with the weight of an equal volume of water </li></ul>
  41. 41. <ul><li>Streak </li></ul><ul><li>The color of a mineral when it is in a powdered form. </li></ul><ul><li>Cleavage and Fracture </li></ul><ul><li>Minerals that break along smooth, flat surfaces have cleavage (mica). </li></ul><ul><li>Minerals that break with uneven, rough, or jagged surfaces have fracture (quartz). </li></ul>
  42. 42. Other Properties <ul><li>Attraction to magnets </li></ul><ul><li>Transparency </li></ul><ul><li>Reaction to acid </li></ul>

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