Earth Rocks Science & Minerals How are rocks classified?
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Transcript of Earth Rocks Science & Minerals How are rocks classified?
GraniteIgneous rock is formed when hot, molten rock (melted rock) cools and becomes hardens, becoming solid.
The melting of the rock happens deep within the Earth.
Igneous rocks formed from magma
Some igneous rocks are formed inside the volcano from cooled magma. Trapped magma cools and hardens very slowly over thousands or millions of years. Granite is an example.
Do you remember the 3 minerals of granite?
Igneous rocks formed from magma
Gabbro is a coarse-grained, dark colored, igneous rock that forms inside the volcano. It has time to form large crystals just like granite.
Gabbro also containsa white version of feldspar.
Igneous rocks formed from lava
Magma that erupts from the volcano is called lava.Lava cools and hardened almost instantly when it is exposed to the much cooler temperatures outside the volcano.
Example of lava (volcanic) rocksIndians used this rock to make tools.Quartz
Obsidian is often called what?
“volcanic glass.”
How wouldyou describe the luster of this volcanic rock? What is this rock called?
Example of lava (volcanic) rocks
QuartzBasalt is one of the most common igneous rocks. It can be found on the upper layer of the ocean floor – and is often call …
“pillow basalt.”
Example of lava (volcanic) rockPumice cools rapidly. Gases are trapped inside the rock as it cools …
leaving a rough, holey texture. What do you predict will happen when we put pumice in water? Why do you think this?
Igneous rocks are formed when…
Molten magma or lava cools and hardens.
Let’s Review …
Molten means …
melted
Does magma hardens inside or outside the volcano?
Inside the volcano
Let’s Review …
Slowly or rapidly?
You’re right … very slowly.
Does lava rock hardens inside or outside the volcano?
Outside the volcano
Let’s Review …
Slowly or rapidly?
You’re right! Very rapidly.
Some rocks that form outside of the volcano from cooled lava are:
Obsidian
Let’s Review …
Basalt
Pumice
Very good!
This is our assignment today. Two thinking maps in your science journal!
1. How Rocks are Classified and Formed
2. All About Igneous Rocks
Use your textbook to help you.Chapter 6, Lesson 3.
Be neat, draw, label, describe, give examples, & color.
Your Assignment Today