Igneous Rocks
Obsidian is an extrusive rock
- Igneous rocks form when hot magma or lava becomes solid.
- Magma is melted rock found deep below the Earth's crust, where temperature and pressure are high.
- Lava is molten rock on Earth's surface.
- Slow cooling of the lava causes the formation of large crystals.
- Rapid cooling of the lava causes the formation of a solid mass of small crystals.
- Igneous rocks are classified by their texture and their mineral composition.
- The different texture of igneous rock are:
- Fine-grained
- Course-grained
- Porphyritic
- Glassy
- Silica is the most abundant igneous rock.
- Igneous rocks are divided into two groups depending on how they are cooled.
1) Intusive
2) Extrusive
- Magma is melted rock found deep below the Earth's crust, where temperature and pressure are high.
- Lava is molten rock on Earth's surface.
- Slow cooling of the lava causes the formation of large crystals.
- Rapid cooling of the lava causes the formation of a solid mass of small crystals.
- Igneous rocks are classified by their texture and their mineral composition.
- The different texture of igneous rock are:
- Fine-grained
- Course-grained
- Porphyritic
- Glassy
- Silica is the most abundant igneous rock.
- Igneous rocks are divided into two groups depending on how they are cooled.
1) Intusive
2) Extrusive