1. © 2012 Pearson Education, Inc. Earth Science, 13e Tarbuck & Lutgens

2. © 2012 Pearson Education, Inc. Matter and Minerals Earth Science, 13e Chapter 2 Stanley C. Hatfield Southwestern Illinois College

3. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. Periodic table of the elements Periodic table of the elements

6. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. Periodic table of the elements Periodic table of the elements

8. © 2012 Pearson Education, Inc. Simplified view of the atom

9. © 2012 Pearson Education, Inc. 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

10. © 2012 Pearson Education, Inc. 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

11. © 2012 Pearson Education, Inc. Minerals Optical properties of minerals ◦ Habit – common crystal shape ◦ Luster – appearance in reflected light ◦ Color ◦ Streak – color of mineral in powdered form

12. © 2012 Pearson Education, Inc. Good crystals of the mineral pyrite

13. © 2012 Pearson Education, Inc. Galena displays metallic luster

14. © 2012 Pearson Education, Inc. Minerals Physical properties of minerals ◦ Fracture – random pattern of breakage ◦ Specific gravity – mineral density ◦ Hardness – ability to resist scratching or abrasion ◦ Cleavage – tendency to break along planes of weak bonding ◦ Other properties  Taste  Smell  Elasticity  Malleability  Feel  Magnetism  Double Refraction  Reaction to hydrochloric acid

15. © 2012 Pearson Education, Inc. Mohs scale of hardness

16. © 2012 Pearson Education, Inc. Conchoidal fracture Conchoidal fracture

17. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. Composition of continental crust

19. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. The silicate (SiO 4 ) -4 molecule

21. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. Hornblende – a member of the amphibole group Hornblende – a member of the amphibole group

23. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. Potassium feldspar Potassium feldspar

26. © 2012 Pearson Education, Inc. Minerals Mineral groups ◦ Nonsilicate minerals  Major groups  Oxides  Sulfides  Carbonates  Halides  Native elements

27. © 2012 Pearson Education, Inc. Common nonsilicate mineral groups Common nonsilicate mineral groups

28. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. 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. © 2012 Pearson Education, Inc. An underground halite (salt) mine

31. © 2012 Pearson Education, Inc. End of Chapter 2