1. Earth Science, 13e
Tarbuck & Lutgens

2. Matter and Minerals Earth Science, 13e Chapter 2
Stanley C. Hatfield
Southwestern Illinois College

3. Minerals: the building blocks of rocks
Definition of a mineral
Natural
Inorganic
Solid
Possess an orderly internal structure of atoms
Have a definite chemical composition
Rock – any naturally occurring solid mass of mineral or mineral-like matter

4. Composition and structure of minerals
Elements
Basic building blocks of minerals
Over 100 are known
Atoms
Smallest particles of matter
Have all the characteristics of an element

5. Periodic table of the elements

6. How atoms are constructed
Nucleus – central part of an atom that contains
Protons – positive electrical charges
Neutrons – neutral electrical charges
Energy levels, or shells
Surround nucleus
Contain electrons – negative electrical charges

7. Simplified view of the atom

8. How atoms are constructed
Atomic number is the number of protons in an atom’s nucleus
Bonding of atoms
Forms a compound with two or more elements
Ions are atoms that gain or lose electrons
Isotopes
Have varying number of neutrons

9. How atoms are constructed
Isotopes
Have different mass numbers – the sum of the neutrons plus protons
Many isotopes are radioactive and emit energy and particles

10. Minerals Physical properties of minerals Habit – common crystal shape
Luster – appearance in reflected light
Color
Streak – color of mineral in powdered form
Hardness – ability to resist scratching or abrasion
Cleavage – tendency to break along planes of weak bonding

11. Good crystals of the mineral pyrite

12. Galena displays metallic luster

13. Mohs scale of hardness

14. Minerals Physical properties of minerals
Fracture – random pattern of breakage
Specific gravity – mineral density
Other properties
Taste
Smell
Elasticity
Malleability

15. Conchoidal fracture

16. Minerals Physical properties of minerals Other properties Feel
Magnetism
Double Refraction
Reaction to hydrochloric acid

17. Minerals A few dozen minerals are called the rock-forming minerals
The eight elements that compose most rock-forming minerals are oxygen (O), silicon (Si), aluminum (Al), iron (Fe), calcium (Ca), sodium (Na), potassium (K), and magnesium (Mg)
Most abundant atoms in Earth’s crust are oxygen (46.6% by weight) and silicon (27.7% by weight)

18. Composition of continental crust

19. Minerals Mineral groups Rock-forming silicates
Most common mineral group
Contain the silicon-oxygen tetrahedron (molecule)
Four oxygen atoms surrounding a much smaller silicon atom
Combines with other atoms to form the various silicate structures

20. The silicate (SiO4)-4 molecule

21. Minerals Mineral groups Rock-forming silicates
Groups based upon tetrahedral arrangement
Olivine – independent tetrahedra
Pyroxene group – tetrahedra are arranged in chains
Amphibole group – tetrahedra are arranged in double chains

22. Hornblende – a member of the amphibole group
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23. Minerals Mineral groups Rock-forming silicates
Groups based upon tetrahedral arrangement
Micas – tetrahedra are arranged in sheets
Two types of mica are biotite (dark) and muscovite (light)
Feldspars – Three-dimensional network of tetrahedra

24. Minerals Mineral groups Rock-forming silicates
Groups based upon tetrahedral arrangement
Feldspars – most abundant group of minerals in Earth’s crust
Quartz – three-dimensional network of tetrahedra

25. Potassium feldspar
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26. Minerals Mineral groups Nonsilicate minerals Major groups Oxides
Sulfides
Carbonates
Halides
Native elements

27. Common nonsilicate mineral groups
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28. Minerals Mineral groups Nonsilicate minerals Carbonates
A major rock-forming group
Found in the rocks limestone and marble
Halite and gypsum are found in sedimentary rocks
Many have economic value

29. Minerals Mineral resources
Mineral resources are occurrences of useful minerals that will eventually be extracted
Ore deposits are concentrations of metallic minerals that can be mined at a profit
Economic factors may change and influence a resource

30. An underground halite (salt) mine

31. End of Chapter 2