1. Minerals Chapter 8

2. Minerals "A mineral is an element of chemical compound that is normally crystalline and that has been formed as a result of geological processes" (Nickel, E. H., 1995). Minerals are naturally-occurring inorganic solid that has a specific chemical composition and crystal structure

3. Minerals 2500 Different Minerals 100 Considered Common Minerals Fewer than 20 (most common) – considered rock forming minerals

4. Eight elements make up 98% percent of Earth’s Crust Oxygen 46.6 % Silicon 27.7 % Aluminum 8.1 % Iron 5.0 % Calcium 3.6 % Sodium 2.8 % Potassium 2.6 % Magnesium 2.1 % Others 1.5 %

5. Mineralogist A scientist who studies minerals including rock- forming minerals

6. Characteristics of Minerals Occurs naturally in the Earth Inorganic-not formed from living or once living things Solid Specific chemical composition Atoms arranged in a definite repeating pattern

7. Minerals Crystals are a solid that have regular shape and flat sides called faces A Geode is a hollow rock that is lined with crystals.

8. Crystal Shapes Tetragonal

9. Crystal Shapes Cubic

10. Crystal Shapes Hexagonal

11. Crystal Shapes Orthorhombic

12. Crystal Shape Monoclinic

13. Crystal Shape Triclinic

14. Uses of Minerals

15. Ores Minerals from which metals and nonmetals can be removed in usable amounts Gold

16. Malleability The ability of a substance to be hammered into thin sheets without breaking

17. Ductility Ability of a substance to be pulled into thin strands without breaking

18. Smelting Process during which ore is heated in such a way that metal can be separated from it

19. Gems Gems are 1) Rare2) Durable 3) Beautiful

20. Precious Stones Rarest and most valuable

21. Semi-Precious Stones Not as Rare and Valuable Hardness of less than 7 Opal Garnet

22. Mineral Identification Minerals can be identified by their color and texture Beryl-Emeralds

23. Color Easily observed, however many minerals come in a variety of colors and some are colorless; in addition, the color of minerals can change as a result of exposure to or treatment with heat, cold, pollution or radiation

24. Texture The way a mineral feels.(greasy, earthy, etc. Talc

25. Luster Describes the way the mineral reflects light from its surface Two types-Metallic and Non-metallic

26. Metallic Luster Chalcopyrite Metallic Luster

27. Nonmetallic Luster Kaolinite Non-Metallic Luster

28. Vitreous Vitreous-Glassy Tourmaline

29. Pearly Looks like the shiny quality of pearls

30. Greasy Sun tan oil look Graphite

31. Silky Shines like silk Schorl

32. Adamantine Brilliant, like a cut diamond The Hope Diamond

33. Hardness Mineral’s ability to resist being scratched

34. Mohs Hardness Scale Talc1 Gypsum2 Calcite3 Fluorite4 Apatite5 Feldspar6 Quartz7 Topaz8 Corundum9 Diamond10

35. Field Hardness Test 1Easily scratched by fingernail 2Scratched by fingernail 3Easily scratched by a house nail; Will not scratch a copper penny 4Easily scratched by nail 5Difficult to scratch with nail; Will not scratch glass

36. Field Hardness Test (cont.) 6.May barely scratch glass; will not scratch steel file 7.May barely scratch steel file Will scratch glass 8-10. Easily scratches a steel file

37. Streak Color of the powder scraped off a mineral when it is rubbed against a streak plate Streak Plate-an unglazed piece of porcelain

38. Density Mass per Unit Volume

39. Specific Gravity Ratio between the Mass of a mineral and the Mass of an equal volume of water

40. Cleavage Occurs when a mineral splits along smooth, definite surfaces Calcite Cleavage

41. Fracture Conchoidal Fracture-Curved Like a Rainbow

42. Fracture Hackly Fracture- Uneven, like broken glass Anhydrite

43. Fracture Splintery or Fibrous Fracture- Breaks into fibers

44. Special Properties Double Refraction- Causes a beam of light to be split in two, producing a double image Calcite

45. Special Properties Magnetism-Acts like a weak magnet Magnetite

46. Special Properties Fluorescence- Mineral glows under UV light

47. Special Properties Phosphorescence- Release of visible light, resulting from the absorption of UV light

48. Special Properties Radioactivity- Release of energy by certain elements due to the decay of an atom into a lighter nucleus Uraninite Metatorbernite

49. Mineral Groups Silicates-Made of Oxygen and Silicon-Orthoclase Sulfates-Made of Oxygen and Sulfur- Barite Oxides-Made of oxygen and usually a Metal-Hematite Halides-Made of Chlorine or Fluorine and Sodium, Potassium, or Calcium Carbonates-Made of Carbon and Oxygen-Dolomite Halite

50. Mineral Examples Azurite Graphite Malachite Sulfur Sapphire