1. Minerals
Chapter 2Earth Materials— Minerals and Rocks
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2. Earth Materials – Minerals
Minerals are the basic units that make up most of Earth’s inorganic materials
Minerals have many essential uses Can you name a few?

3. What is a mineral?

4. What is a mineral?
1. It is formed naturally

5. What is a mineral? 1. It is formed naturally
2. It has a crystalline structure

6. What is a mineral? 1. It is formed naturally
2. It has a crystalline structure
3. It is solid

7. What is a mineral? 1. It is formed naturally
2. It has a crystalline structure
3. It is solid
4. It has a narrowly defined chemical composition

8. What is a mineral? 1. It is formed naturally
2. It has a crystalline structure
3. It is solid
4. It has a narrowly defined chemical composition
5. It has characteristic physical properties

9. What is a mineral? 1. It is formed naturally
2. It has a crystalline structure
3. It is solid
4. It has a narrowly defined chemical composition
5. It has characteristic physical properties
6. It is inorganic -- never living

10. Minerals Chemical composition:
composed of elements Quartz – SiO2 composed of one silicon atom and two oxygen atoms
Distinct Properties: color, luster, hardness, breakage, streak, taste, odor, magnetic, surface features, reactive with acid

11. Matter and Its Composition
Every substance on earth is composed of “matter”
Matter has mass and volume
(occupies space) solid, liquid, gas composed of elements
Elements are chemical substances
cannot be broken down chemically
composed of atoms

12. Atoms smallest particle that retains the nature of the element
Nucleus contains particles
protons: + neutrons: no charge
Electrons travel around the nucleus
electrons: --

13. Structure of an Atom The dense nucleus of an atom
consisting of protons and neutrons
is surrounded by a cloud of orbiting electrons

15. Particles in nucleus
Atomic number: the number of protons This determines the name of the element.
Atomic mass number is the
number of protons + number of neutrons
The number of neutrons in an atom
may vary without changing the name of the element

16. When neutrons vary
Isotopes of the same element are formed Isotopes have the same atomic number
Isotopes have different atomic mass numbers
Isotopes of the same element behave the same chemically
Isotopes are important in
radiometric dating

17. Carbon Isotopes Carbon atoms (with 6 protons)
have 6 neutrons = Carbon 12 (12C)
have 7 neutrons = Carbon 13 (13C)
or have 8 neutrons = Carbon 14 (14C)
thereby making up three isotopes of carbon.

18. Bonding and Compounds Bonding: atoms join to other atoms
Compound bonding of two or more elements
Oxygen gas (O2) is an element
Ice (H2O) is a compound
Most minerals are compounds

19. Atomic Bonding
Ionic bonds: electrons are donated or received

20. Atomic Bonding Common types of bonding among atoms to form minerals:
Ionic bonds: electrons are donated or received

21. Atomic Bonding Common types of bonding among atoms to form minerals:
Ionic bonds: electrons are donated or received
Covalent bonds: electrons are shared

22. Atomic Bonding Common types of bonding among atoms to form minerals:
Ionic bonds: electrons are donated or received
Covalent bonds: electrons are shared
Metallic bonds: electrons are located in a “cloud” around nucleus

23. Atomic Bonding Common types of bonding among atoms to form minerals:
Ionic bonds: electrons are donated or received
Covalent bonds: electrons are shared
Metallic bonds: electrons are located in a “cloud” around nucleus
Vanderwaals bonds: atoms are weakly attracted

24. Ionic Bonding
Ion: atom that has gained or lost one or more electrons It has a negative or positive charge
Ionic bonding
attraction between two ions of opposite charge
Goal: atoms are more stable when outer electron shell is filled.

25. Ionic Bonding

26. halite

27. Covalent Bonding Covalent bonding shared electrons
results from sharing electrons
shared electrons

28. Metallic Bonding
Electrons are loosely arranged in a “cloud-like” arrangement. Metals have properties of being good electrical conductors Metals are malleable

29. Minerals—The Building Blocks of Rocks
Quartz consists of 1 silicon atom for every 2 oxygen atoms
Quartz: SiO2
Ratio: 1: 2
Potassium Feldspar consists of 1 potassium, 1 aluminum, and 3 silicon for every 8 oxygen atoms
KAlSi3O8
1: 1: 3: 8

30. Native Elements consist of only one element. They are not compounds.
gold – formula: Au
diamond – formula: C

31. Allotropes of carbon “polymorphs”

32. Mineral Properties controlled by internal arrangement of atoms
Chemical composition
Crystalline structure

33. Color how reliable is color to identify a mineral?
Many varieties of quartz

34. Crystal form If given enough room to grow freely
minerals form perfect crystals with
planar surfaces, called crystal faces
sharp corners
straight edges

35. Moh’s Scale of hardness arranged from 1 to 10
Hardness is a mineral’s resistance to abrasion or being scratched

36. Streak test color of a mineral in its powdered form

37. Breakage yes, they all break, but some break in predictable patterns
Irregular breakage or fracture: random, smooth, round (conchoidal) with no geometric shape or parallel flat sides

38. Breakage
Cleavage:
tendency to break in flat surfaces that are parallel may have one, two, three, even four pairs of flat sides, or planes.

39. Types of mineral cleavage

40. Surface feature - feldspars
Exsolution Lamellae Potassium Feldspar
Striations Plagioclase Feldspar

41. Unique taste, odor halite and sulfur

42. Reaction with dilute hydrochloric acid – carbonate minerals

43. Common rock forming minerals

44. Rock-Forming Minerals
Most rocks are solid aggregates of one or more minerals
Thousands of minerals occur in rocks,
but most rocks have common rock-forming minerals
Most rock-forming minerals are silicates,
but other groups are important

45. Silicates Silicates are minerals containing silica
Si and O
They make up perhaps 95% of Earth’s crust
and account for about 1/3 of all known minerals

46. The basic building block of silicates
is the silicon oxygen tetrahedron
which consists of one silicon atom
surrounded by four oxygen atoms

47. Earth’s crust: elements by weight %

48. Types of Silicates Silica tetrahedra can be
isolated units bonded to other elements
arranged in chains (single or double)
arranged in sheets
arranged in complex 3D networks

49. Types of Silicates Ferromagnesian silicates (dark)
contain iron (Fe), magnesium (Mg), or both
olivine, pyroxene, amphibole, biotite
Nonferromagnesian silicates (light) contain potassium (K), sodium (Na), (Ca)calcium
Quartz, muscovite, feldspar

50. Ferromagnesian Silicates
Common ferromagnesian silicates include
Pyroxene-
olivine
biotite mica
amphibole

51. Nonferromagnesian Silicates
Quartz Potassium feldspar
Plagioclase feldspar Muscovite

53. Other Mineral Groups
Carbonates contain carbonate ion CO3 (CaCO3) calcite Oxides (Fe2O3) Magnetite Halides ( NaCl) Halite Sulfides (PbS) Galena