Minerals, Rocks, Mountains, and Deforestation

Posted on Jan 20, 2025 in Geology

Types of Luster in Minerals

Metallic: Resembles metal, for example, pyrite.

Non-metallic: Includes various types such as:

  • Waxy: Resembling oil or fat.
  • Dull: Not shiny.
  • Glassy: Resembling glass.

How Are Mountains Formed?

Mountains are formed through a combination of processes, including:

  • Erosion
  • Transportation
  • Weathering
  • Fulmination

All You Need to Know About Slate

Slate is a foliated rock. It is usually black and slightly shiny due to the presence of mica. It is hard but can be separated into thin layers or sheets (foliation).

Difference Between Intrusive and Extrusive Rocks

  • Plutonic (intrusive) rocks: Form as magma cools slowly underground over thousands of years. As a result, the mineral crystals are large.

  • Volcanic (extrusive) rocks: Form as lava cools rapidly on the Earth’s surface. As a result, the mineral crystals are tiny.

Characteristics of Sedimentary Rocks

Sedimentary rocks are made up of fragments of other rocks. The deposition of these sediments in layers, in lakes or seas, takes place over millions of years. The deposited sediments are transformed into compact, cohesive rocks.

Compaction and Cementation

  • Compaction: The weight of successive layers of sediment compacts the sediments further. This pressure reduces the spaces between the fragments and squeezes out the water. As a result, salt crystals are formed.

  • Cementation: The rock fragments are stuck together with the salt crystals which formed when the water was eliminated.

Each layer of sediments is transformed into a layer of sedimentary rock. This layer is called a stratum (plural strata).

Mountain Erosion

Here’s how mountains erode:

  1. After heavy rain, rivers transport mud into valleys.
  2. Rivers transport particles.
  3. The wind transports sand.
  4. Layers of sediment build up.

What All Minerals Have in Common

  • Color: Some minerals are always the same color. For example, sulfur is always yellow, while quartz can be different colors.

  • Shape: Minerals can be geometric or irregular.

  • Luster: Refers to the way minerals reflect light. Minerals can be classified as:

    • Metallic: Like metal, for example, pyrite.
    • Non-metallic: Waxy like oil or fat, dull not shiny, or glassy like glass.

  • Streak: The streak of a mineral is the color of the powder left on a streak plate (a piece of unglazed porcelain) when the mineral is scraped across it.

  • Cleavage: Is how a mineral breaks up or cleaves. For example, mica cleaves in sheets, but galena cleaves in cubes.

  • Hardness: Measures how a mineral reacts to being scratched.

Deforestation

What is deforestation?: The cutting down of natural forests by logging and burning.

What are the four causes of deforestation?

  1. The world demands timber for building materials and paper.
  2. The clearing of land for agriculture and cattle ranches.
  3. Clearing for the construction of new roads and towns.
  4. To provide firewood and chemicals as fuels.

Deforestation increases the amount of CO2 in the atmosphere, contributing to global warming.

What are the three solutions for deforestation?

  1. Reforestation: The replanting of native trees.
  2. Sustainable management of forests.
  3. Recycling and energy conservation.