Igneous Rocks

What is an Igneous rock?

There are two kinds of igneous rocks...1. Extrusive igneous rocks are lava exposed to air or water causing it to cool rapidly.

2.Intrusive rocks are rocks that cool under the Earths surface. It can take 100yrs or so just to cool a few degrees, just from all the heat and pressure! Slowly cooling causes crystals to form also.

WHAT ARE SOME IGNEOUS ROCKS?

• Types of igneous rocks:
• Obsidian is a extrusive rock.
• Pink granite is an intrusive rock.(since it contains minute crystals formed under ground.)
• Pumice is an extrusive rock, because it has been exposed to air, while cooling. That is why it is able to float.
• Basalt, is the most common extrusive rock, and is made of small crystals.

Pumice facts:
Pumice is used to remove dead skin cells.
Pumice is also used for grinding and polishing.
It is able to form under water.

Igneous rocks are either cooled under ground or on earths crust.
Those are the only two places that they cool at.

"5"FUN FACTS!!!

• Granite is a intrusive rock that is a common building material.
• Obsidian has been used for weapons and sharp tools.
• Obsidian is also known as volcanic glass. Example: obsidian is a extrusive rock that has no crystals!
• Igneous rocks can turn into metamorphic rocks.(heat and pressure!)
• Tuff , obsidian, scoria, and basalt are extrusive.

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IGNEOUS EXAMPLE

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IGNEOUS ROCK.