Earth Materials Summary Notes

Earth Materials Overview

• Minerals are solid, naturally occurring inorganic materials with a crystalline structure and definite chemical composition.
• Rocks are aggregates consisting of minerals or mineral-like substances.
• Soil is composed of decayed organic matter mixed with broken down rocks and minerals.
• Water, a vital molecule made of hydrogen and oxygen, is essential for life.
• Energy sources are classified into renewable (inexhaustible) and non-renewable (depletable).

Characteristics of Minerals

• Minerals are solid at room temperature.
• They possess a distinct crystalline structure.
• Inorganic classification means they are not derived from living organisms.
• Each mineral has a definable chemical composition.
• Minerals exhibit homogeneity throughout their structure.
• Naturally occurring in the Earth's crust.

Formation of Minerals

• Solidification of a melt occurs when liquid substances freeze to form solid minerals.
• Precipitation from a solution happens when atoms or ions bond and crystallize upon evaporation.
• Solid-state diffusion involves atomic movement through solid matrices.
• Biomineralization is the process by which animals create minerals to strengthen tissues.
• Fumarolic mineralization refers to the precipitation of minerals from volcanic gases.

Physical Properties of Minerals

• Crystal Form: Reflects the internal atomic arrangement.
• Luster: Determines light reflection quality (metallic vs. non-metallic).
• Color: Often unreliable; can vary in different specimens.
• Streak: The color observed when a mineral is powdered.
• Cleavage: The tendency of minerals to break along defined planes.
• Fracture: Describes the mineral's breaking pattern (e.g., quartz).
• Specific Gravity: Ratio of mineral weight to an equal volume of water.
• Hardness: A measure of resistance to scratching and abrasion.

Types of Minerals

• Metallic Minerals*
• Examples include iron, nickel, copper, gold, silver, chromium, zinc, mercury, lead, and platinum.
• Non-metallic Minerals*
• Examples include silica, clay, and marble.

Mineral Groups

• Silicates*
• Predominant in the Earth's crust, containing silicon and oxygen.
• Built around the silicon-oxygen tetrahedron (SiO₄).
• Include quartz (SiO₂), feldspar, mica, olivine, pyroxene, and amphibole.
• Non-silicates*
• Lack silicon-oxygen tetrahedra.
• Composed of chemical elements like carbonates, sulfates, oxides, and halides.
• Notable examples:
  • Carbonates: Calcite (CaCO₃) found in limestone.
  • Sulfates: Gypsum (CaSO₄·2H₂O), used in construction.
  • Oxides: Hematite (Fe₂O₃) and magnetite (Fe₃O₄) are essential iron ores.
  • Halides: Rock salt (Halite, NaCl).
  • Sulfides: Pyrite (FeS₂), known as fool's gold.

Types of Rocks

• Igneous Rocks: Form from molten material, categorized as intrusive (coarse-grained) or extrusive (fine-grained).
• Sedimentary Rocks: Formed from sediment deposits, divided into clastic, chemical, and organic types.
• Metamorphic Rocks: Result from existing rocks altered under high pressure and temperature, including both foliated and non-foliated varieties.

Energy Resources

• Non-renewable Energy Sources*
• Fossil fuels derived from ancient organisms include:
  • Coal: A solid fossil fuel, mainly used for electricity generation.
  • Oil: A liquid fossil fuel, processed for various applications.
  • Natural Gas: Primarily methane, used in cooking and heating.
• Renewable Energy Sources*
• Solar Energy: Generates electricity from sunlight.
• Wind Energy: Converts wind motion into electrical energy.
• Geothermal Energy: Harnesses heat from beneath the Earth's surface.
• Hydroelectric Energy: Utilizes flowing water to produce electricity.
• Biomass: Fuel and energy derived from organic materials.
• Nuclear Energy: Electricity generated through nuclear fission processes.