1. Inside the Restless Earth
Ch. 1
Minerals of
the Earth’s Crust

2. Section 1: What Is a Mineral?

3. Section 1: What is a Mineral?
Naturally formed
Inorganic
Solid
Crystalline structure

4. Mineral Structure
element - a substance that cannot be separated or broken down into simpler substances by chemical means.
Each element is made of only one kind of atom.
The element sodium.

5. Tom Lehrer's The Elements.mht

6. Mineral Structure
compound - a substance made of two or more elements that have been chemically combined.
Na + Cl = NaCl
The compound halite.

7. Mineral Structure
crystal - a solid whose atoms, ions, or molecules are arranged in a definite repeating pattern.
The arrangement of atoms
is determined by the kinds
of atoms.
Amethyst.

8. Two Groups of Minerals
Minerals are divided into two groups based on their chemical composition.

9. Two Groups of Minerals
1. Silicate minerals - minerals that contain a combination of silicon, oxygen, and often one or more metals.
- Make up > 90% of Earth’s crust

10. Common Silicate Minerals
Feldspar
KAlSi3O8
Quartz
Silicon Dioxide
SiO2
Mica
Biotite
K(Mg, Fe)3AlSi3O10(F, OH)2

11. Two Groups of Minerals
2. Nonsilicate minerals - minerals that do not contain compounds of silicon and oxygen.
Gypsum

12. Classes of Nonsilicate Minerals
Native Elements - composed of only one element.
Gold
Copper

13. Classes of Nonsilicate Minerals
Oxides - form when an element (such as aluminum or iron) combines chemically w/ oxygen.
Corundum
Al2O3
Aluminum oxide

14. Classes of Nonsilicate Minerals
Carbonates - contain combinations of carbon and oxygen in their chemical structure.
Calcite
CaCO3

15. Classes of Nonsilicate Minerals
Sulfates - contain sulfur and oxygen, SO4.
Gypsum
Calcium Sulfate Dihydrate
CaSO4·2H2O

16. Classes of Nonsilicate Minerals
Halides - form when:
flourine, chlorine, iodine, or bromine
combine with
sodium, potassium, or calcium
Flourite
Calcium Fluoride
CaF2

17. Classes of Nonsilicate Minerals
Sulfides - contain one or more elements (such as lead, iron, or nickel) combined with sulfur.
Galena
Lead Sulfide
PbS

18. Section 2: Identifying Minerals

19. Section 2: Identifying Minerals
Color
- the same mineral can come in a variety of colors
- usually not the best way to identify a mineral

20. Section 2: Identifying Minerals
Luster - the way a surface reflects light.

21. Section 2: Identifying Minerals
Luster - the way a surface reflects light.
1. Metallic - bright, reflective
Gold

22. Section 2: Identifying Minerals
2. Submetallic - dull, reflective
Euxenite

23. Section 2: Identifying Minerals
3. Nonmetallic
Vitreous
glassy, brilliant
Pollucite

24. Section 2: Identifying Minerals
3. Nonmetallic
Silky
fibrous
Gypsum

25. Section 2: Identifying Minerals
3. Nonmetallic
Resinous
plastic
Sphalerite

26. Section 2: Identifying Minerals
3. Nonmetallic
Waxy
greasy, oily
Cancrinite

27. Section 2: Identifying Minerals
3. Nonmetallic
Pearly
creamy
Stellerite

28. Section 2: Identifying Minerals
3. Nonmetallic
Earthy
rough, dull
Kaolinite

29. Section 2: Identifying Minerals
Streak - the color of a mineral in powdered form.
- the mineral is rubbed
against a streak plate
- streak is not affected
by air or water
- more reliable than
mineral color

30. Cleavage and Fracture
Cleavage - the tendency of some minerals to break along smooth, flat surfaces.

31. Cleavage and Fracture
Fracture - the tendency of some minerals to break unevenly along curved or irregular surfaces.
Conchoidal fracture

32. Hardness
Hardness - a mineral’s
resistance to being
scratched.

33. Density
Density - measure of how much matter is in a given amount of space. d = m / v
gold = 19 g/cm3
Specific gravity - the ratio of an object’s density to the density of water.
gold = 19

34. Special Properties Fluorescence - glow under ultraviolet light.
Calcite (red) and willemite (green)

35. Special Properties
Chemical reaction - look for bubbling when combined with an acid.
CaCO3 + 2HCl = CO2 + H2O + CaCl2
calcite
hydrochloric acid

36. Special Properties Optical properties - such as double refraction.
Same sample of calcite, but it’s rotated.

37. Special Properties
Magnetism - attracts iron.
Magnetite

38. Special Properties Taste Never taste a mineral without the
teacher’s permission.
Halite tastes salty.
Borax tastes sweet.

39. Special Properties
Radioactivity
Autunite contains uranium.

40. Section 3: The Formation, Mining, and Use of Minerals

41. How Do Minerals Form? Limestones
As water runs along the surface of the Earth and
seeps through the ground, it dissolves minerals and
carries them to large
bodies of water, where
they crystallize on the
bottom.

42. How Do Minerals Form? Evaporating Salt Water
Minerals such as halite crystallize when salt water
evaporates.

43. How Do Minerals Form? Metamorphic Rocks
Changes in pressure, temperature, or chemical
makeup can form new minerals such as garnet.

44. How Do Minerals Form? Hot-Water Solutions
Magma heats groundwater, which now more easily
reacts with and dissolves minerals. The minerals
then crystallize out of
the solution. This
vein of gold was
formed this way.

45. How Do Minerals Form? Pegmatites
Magma can move upward into these teardrop-shaped
bodies. Pictured here is a sample of tourmaline from
a pegmatite.

46. How Do Minerals Form? Plutons As magma moves up it may cool and
solidify forming a
pluton.

47. Mining Ore: A mineral deposit large enough and pure enough to
be mined for profit.

48. Mining Surface Mining Used to remove minerals located at or near the
surface of the Earth.

49. Mining Subsurface Mining Used to remove minerals
located too deep within the
Earth to be surface mined.

50. Responsible Mining Potential mining problems:
- Can disturb or destroy habitats
- Waste products may pollute surface water and
groundwater

51. Responsible Mining Potential mining problems: Solutions:
- Can disturb or destroy habitats
- Waste products may pollute surface water and
groundwater
Solutions:
- Reclamation: return mined land to its original state
- Reduce need for minerals by recycling

52. The Use of Minerals Metallic Minerals - Have shiny surfaces
- Do not let light pass
through them
- Good conductors of heat
and electricity

53. The Use of Minerals Nonmetallic Minerals - Have shiny or dull surfaces
- May let light
pass through
them
- Good insulators
of electricity

54. The Use of Minerals
Gemstones
- Highly valued for beauty and rarity