Geology 101: Chapter 3 - Physical Geology

Lecture on Minerals

Overview

• Focus on understanding minerals: definition, formation, and differentiation from rocks.
• Importance of distinguishing minerals from rocks for further geological studies.

Basic Chemistry Review

• Matter: Anything with mass and occupies space.
• States of Matter: Solids, liquids, gases (and plasma, not covered here).
• Atoms and Elements: Building blocks of matter.
  • Oxygen, hydrogen, helium as examples.
  • Structure: Protons (+), Neutrons (0), Electrons (-).
  • Atomic Number: Number of protons (e.g., Oxygen = 8).
• Isotopes: Atoms of the same element with different neutrons.

Bonding

• Ionic Bonds: Transfer of electrons (e.g., Sodium chloride - NaCl).
• Covalent Bonds: Sharing of electrons (e.g., Water - H2O).

Definition of Minerals

• Criteria:
  • Naturally occurring.
  • Inorganic.
  • Crystalline solid.
  • Defined chemical composition.
  • Distinctive physical properties.
• Examples: Ice as a mineral (but not water).

Types of Minerals

• Elemental Composition:
  • Silicon and Oxygen are predominant in Earth's crust.
  • Silicates are the most common mineral group.
• Silicate Types:
  • Ferromagnesian (contain iron/magnesium, dark).
  • Non-ferromagnesian (do not contain iron/magnesium, light).
• Other Mineral Groups: Carbonates, Sulfates, Native Elements (e.g., Gold, Silver).

Identification of Minerals

• Physical Properties:
  • Luster: Metallic vs. Non-metallic.
  • Color.
  • Crystal Form.
  • Cleavage (natural breakage) vs. Fracture (irregular breakage).
  • Hardness (Mohs Scale from Talc to Diamond).
  • Density: Metallic minerals are denser.
  • Others: Texture, taste, magnetism, streak, reaction to acid.

Differences between Minerals and Rocks

• Minerals: Building blocks of rocks, unique composition.
• Rocks: Combination of minerals.
  • Example: Granite composed of Feldspar, Quartz, Biotite.

Upcoming Topics

• Chapter 4 & 5: Formation of igneous rocks, magma, lava.
• Chapter 6: Sedimentary processes.
• Chapter 7: Changes in Earth's materials through heat, pressure, chemical reactions.

Next Steps

• Review the chapter notes.
• Complete the homework for Chapter 3.
• Proceed to the video lecture on the Rock Cycle and then Igneous Rocks.

Ensure to attend office hours or utilize the discussion board for any questions. Happy studying!