1. Chapter 1 Minerals: Building Blocks of Rocks

2. Minerals: Building Blocks of Rocks
By definition a mineral is/has
Naturally occurring
Inorganic solid
Ordered internal molecular structure
Definite chemical composition

3. Where do minerals form Plate boundaries = Igneous and Metamorphic
Oceans and water =
Sedimentary minerals

4. Where do minerals form Magma Slow cooling = large crystals
Fast cooling = small crystals

5. Where do minerals form Sedimentary Precipitation of minerals
from water

6. Where do minerals form Metamorphic Minerals
Heating and recrystallization
of existing rocks

7. Rocks are an aggregate of minerals

8. Composition and Structure of Minerals
Atoms Elements Minerals Rocks

9. Composition and Structure of Minerals
Elements
Basic building blocks of minerals
Over 100 are known (92 naturally occurring)
Atoms
Smallest particles of matter
Retain all the characteristics of an element

10. Composition and Structure of Minerals
Atomic structure
Central region called the nucleus
Consists of protons (+ charges) and neutrons (- charges)
Electrons
Negatively charged particles that surround the nucleus
Located in discrete energy levels called shells

11. Structure of an Atom

12. Fig. 7.5

13. Structure of an Atom

14. Ionic Bonding –
Transfer of Electronics

15. Covalent Bonding – Sharing of Electronics

16. Composition and Structure of Minerals
Chemical bonding
Formation of a compound by combining two or more elements
Atoms gain or lose outermost electrons to form ions
Oppositely charged ions attract one another to produce a neutral chemical compound

17. Composition and Structure of Minerals
Isotopes and radioactive decay
Mass number = sum of neutrons + protons in an atom
Isotope = atom that exhibits variation in its mass number
Unstable isotopes emit particles and energy in a process known as radioactive decay

18. Earth Composition
Earth Consists of the Core, Mantle, and Crust

19. Elemental Abundances in Continental Crust
Figure 1.14

20. Elemental Abundances Earth as a whole vs Crust
Oxygen 35%
Iron 24%
Silicon 17%
Magnesium 14%
Sulfur 6%
Aluminum 1%
Calcium 1%
Oxygen 47%
Iron 5.5%
Silicon 27%
Magnesium 2.1%
Sulfur <1%
Aluminum 8%
Calcium 3.7%

21. Mineral Identification - Crystal Form

22. A Garnet Crystal

23. Cubic Crystals of Pyrite

24. Minerals - Crystals

26. Physical Properties of Minerals
Luster
Appearance of a mineral in reflected light
Two basic categories
Metallic
Nonmetallic
Other descriptive terms include vitreous, silky, or earthy

27. Galena (PbS) Displays Metallic Luster

28. Physical Properties of Minerals
Color
Generally unreliable for mineral identification
Often highly variable due to slight changes in mineral chemistry
Exotic colorations of certain minerals produce gemstones

29. Quartz (SiO2) Exhibits a Variety of Colors

30. Physical Properties of Minerals
Streak
Color of a mineral in its powdered form
Hardness
Resistance of a mineral to abrasion or scratching
All minerals are compared to a standard scale called the Mohs scale of hardness

31. Streak Is Obtained on an Unglazed Porcelain Plate

32. Mohs Scale of
Hardness

33. Diamonds

34. Mohs Scale of Hardness Atom Arrangement
Diamond
Graphite

35. Physical Properties of Minerals
Cleavage
Tendency to break along planes of weak bonding
Produces flat, shiny surfaces
Described by resulting geometric shapes
Number of planes
Angles between adjacent planes

36. Fluorite, Halite, and Calcite All Exhibit Perfect Cleavage

37. Fig f

38. Fig d

39. Fig a

40. Physical Properties of Minerals
Fracture
Absence of cleavage when a mineral is broken
Specific Gravity
Weight of a mineral/weight of an equal volume of water
Average value = 2.5 – 3.0

41. Conchoidal Fracture

42. Physical Properties of Minerals
Other properties
Magnetism
Reaction to hydrochloric acid
Malleability
Double refraction
Taste
Smell
Elasticity

43. Mineral??????? Quartz Yes No Coal Yes No Pearls Yes No Amethyst Yes No
Shells Yes No
Water Yes No
Ice Yes No
Iron Yes No

44. Mineral??????? Quartz Yes No Coal Yes No Pearls Yes No Amethyst Yes No
Shells Yes No
Water Yes No
Ice Yes No
Iron Yes No

45. Mineral Groups Nearly 4000 minerals have been named
Rock-forming minerals
Common minerals that make up most of the rocks of Earth’s crust
Only a few dozen members
Composed mainly of the 8 elements that make up over 98% of the continental crust

46. Mineral Groups Silicates Most important mineral group
Comprise most rock-forming minerals
Very abundant due to large % of silicon and oxygen in Earth’s crust
Silicon-oxygen tetrahedron
Fundamental building block
Four oxygen ions surrounding a much smaller silicon ion

47. Mineral Groups Common silicate minerals Feldspar group Quartz
Most common mineral group
Quartz
Only common silicate composed entirely of oxygen and silicon

48. Two
Illustrations
of the
Si–O
Tetrahedron

49. Silicate Mineral Structures

50. Silicate Mineral Structures

51. Silicate Mineral Structures

52. Potassium Feldspar

53. Mineral Groups Important nonsilicate minerals
Comprise only 8% of Earth’s crust
Often occur as constituents in sedimentary rocks

55. Mineral Groups Important nonsilicate minerals Carbonates
Primary constituents in limestone and marble
Limestone is used commercially for road paving, building stone, and as the main ingredient in Portland cement

56. Mineral Groups Important nonsilicate minerals Halite and gypsum
Both are commonly found in thick layers
Like limestone, both halite and gypsum are important nonmetallic resources

57. Mineral Groups Important nonsilicate minerals
A number of other minerals have economic value
Examples
Hematite (oxide mined for iron ore)
Sphalerite (sulfide mined for zinc ore)
Galena (lead)
Native copper (native element mined for copper)

58. Native Copper

59. Mineral Resources and Reserves
Resources are minerals that can be recovered for use
Reserves include mineral deposits already identified that can be profitability extracted
Resources include reserves, deposits that can not economically recovered, and minerals not yet discovered

60. Florida Production 4th in states for non fuel minerals
Top 3 in the states for crushed stone, cement, and peat
1st in states in heavy mineral sales
1st in world for phosphate production

61. Florida Production - Phosphate
90% used for fertilizer
5% for livestock feed supplement
5% used in food products, chemicals and ceramics

62. Florida Production – Crushed Stone
Limestone and coquina
Used for construction
Limestone used for cement

63. Florida Production – Clays
Used for absorbents, anti-acids, and whiteners

64. Florida Production – Heavy Minerals
Found in Sands
Main minerals include ilmenite and rutile – both metamorphic minerals
Used as paint pigments,
paper, and plastics

65. End of Chapter 1