1. Chapter 2: Earth Materials

2. Elements and Compounds
Most fundamental substance into which matter can be separated by chemical means
Atom
Smallest single particle that keeps element’s distinct chemical properties
Protons (+)
Neutrons (neutral)
Electrons (-)
Net atom charge
Protons (+) + electrons (-)

3. Elements and Compounds
Atomic number
# of protons
Atomic mass
# of protons + # of neutrons
Isotopes
Atoms with same atomic # but different mass #

4. Elements & Compounds Electron (-) Electron “shells” Ion Cation (+)
Anion (-)

5. Compounds, molecules and bonding
Combo of atoms from 1 or more elements in specific ratio
Molecule
Smallest unit with all properties of a specific compound
Bond
Force that holds together atoms in molecules &/or compounds

6. Compounds, molecules & bonding
Ionic Bonding
1 atom transfers electron to another
Gain or lose electrons
I.e. = Table salt (sodium chloride or NaCl)

7. Compounds, molecules and bonding
Covalent Bond
Electrons from different atoms “pair up” & create bond
Share electrons
Strongest of chemical bonds

8. Compounds, molecules and bonding
Metallic Bond
Electrons shared among several atoms
Outer electrons drift between atoms
Good conductors of heat & electricity

9. Compounds, molecules and bonding
Van der Waals Bond
Attraction between electrically neutral molecules with asymmetrical charge
Dipolar molecules
Weak bonds
I.e. Water

10. What Is a Mineral? Mineral Naturally formed Solid Inorganic
Specific crystal structure
Specific chemical composition

11. Composition of minerals
Atomic substitution
Elements with similar size & charge can substitute for each other
Crystal structure
Atoms/molecules arranged into regular patterns
Mineraloid
Polymorphs
Same chemical composition but different crystal structure

12. Telling minerals apart
Luster
Quality & intensity of light reflection
Metallic
Non-metallic
Vitreous
Resinous
Pearly

13. Telling minerals apart
Crystal form
Any flat or planar surface that forms during mineral growth
Habit
Particular mineral’s distinctive shape

14. Telling minerals apart
Hardness
Image
Common Objects Reference
Talc 1
Telling minerals apart 2
Gypsum
Fingernail (2.5)
Calcite 3
Copper Penny (3.5)
Hardness
Mineral’s resistance to scratching
Mohs scale (1-10)
Fluorite 4
Wire Nail (4.5)
Apatite 5
Glass (5.5)
Feldspar 6
Streak Plate (6.5)
Quartz 7
Topaz 8
Corundum 9
Diamond 10

15. Telling minerals apart
Cleavage
Mineral breaks in a regular pattern
Relates to crystal structure within mineral

16. Telling minerals apart
Color
Least reliable
Light absorbed by mineral
Streak
Powdered trace of mineral made by rubbing specimen across unglazed porcelain piece

17. Telling minerals apart
Density
Mass / volume
Compactness of atoms
Other mineral properties
Birefringent
Double images
Effervescence
Fizzes in acid
Magnetic
Attracted to magnet
Luminescence or fluorescence
UV “glow”

18. Mineral families & their uses
Minerals of Earth’s crust
Silicate minerals
Minerals contain both silicon & oxygen
Silicon-oxygen tetrahedron
1 Si atom bonded to 4 O atoms

19. Mineral families & resources
Other minerals of Earth’s crust
Oxides
Carbonates
Ore deposits
Localized concentration that can be extracted profitably

20. Rocks: A First Look Rock
Naturally formed aggregate of minerals & possibly other non-mineral matter
Record history of Earth processes
Biotite
Feldspar
Quartz
Granite

21. Rocks: A First Look Igneous Sedimentary Metamorphic
Form by cooling & solidification of molten rock
Magma
Sedimentary
Form under conditions of low pressure & low temperature near the surface
Metamorphic
Altered by exposure to high temperature, high pressure or both