Moomoomath and Science Video: Types of Rocks

Overview

• Rocks are solid, naturally occurring substances made up of minerals or mineral-like matter.
• They can vary in size from small formations to large structures like canyons.
• Rocks are categorized into three main types based on their formation:
  • Igneous
  • Sedimentary
  • Metamorphic

Igneous Rocks

• Formed from the cooling of magma or molten rock.
• Types:
  • Extrusive (Volcanic): Cool quickly on Earth's surface, have small crystals.
  • Intrusive (Plutonic): Cool slowly beneath Earth's surface, have larger crystals.

Examples of Igneous Rocks

1. Obsidian
   • Type: Extrusive
   • Composition: Quartz, alkali, feldspar
   • Appearance: Glass-like
   • Hardness: 6-7
2. Granite
   • Type: Intrusive
   • Composition: Feldspar, quartz, mica
   • Appearance: Medium to coarse-grain
   • Hardness: 5-5.5
3. Basalt
   • Type: Extrusive
   • Composition: Plagioclase feldspar, pyroxene
   • Characteristics: Dark, dense, fine-grained
   • Hardness: 5-6
4. Scoria
   • Type: Volcanic
   • Composition: Feldspar, augite, hornblende
   • Features: Basalt with cavities
5. Rhyolite
   • Type: Extrusive
   • Composition: Feldspar, quartz, mica
   • Texture: Very fine, porous (can float in water)

Sedimentary Rocks

• Form from pre-existing rocks or organic material.
• Formation: Accumulation of deposits on Earth's surface or under the ocean.
• Types:
  • Clastic: From fragments of pre-existing rocks.
  • Chemical: From precipitation of minerals from water.
  • Organic: From accumulation of plant and animal debris.

Examples of Sedimentary Rocks

1. Shale
   • Type: Clastic
   • Composition: Clay minerals, silt-sized particles
   • Feature: Very fine-grained
2. Sandstone
   • Type: Clastic
   • Composition: Sand-sized grains, cementing material
3. Conglomerate
   • Type: Clastic
   • Composition: Pebbles, boulders filled with calcite or quartz cement
4. Limestone
   • Type: Organic
   • Composition: Skeletal fragments of marine organisms
   • Prevalence: 10% of sedimentary rocks on Earth

Metamorphic Rocks

• Formed from existing rocks under extreme heat and pressure.
• Protolith: Original rock before transformation.
• Types:
  • Foliated: Crystals arranged in stripes.
  • Non-Foliated: No stripe arrangement.

Examples of Metamorphic Rocks

1. Slate
   • Type: Foliated
   • Parent Rock: Shale
2. Marble
   • Type: Non-foliated
   • Parent Rock: Limestone
3. Quartzite
   • Type: Non-foliated
   • Parent Rock: Sandstone
4. Gneiss
   • Type: Foliated
   • Parent Rock: Schist
5. Schist
   • Type: Foliated
   • Parent Rock: Slate

Conclusion

• This video provides a comprehensive overview of rock types and examples.
• For more information, a related playlist is available.
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