Earth Rocks Science & Minerals How are rocks classified?

How are rocks classified There are 3 types of rocks! Igneous Sedimentary Metamorphic

Rocks are classified & identified by … how they are formed.

Igneous Igneous: from the Greek word “fire”

Granite Igneous 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.

Volcano Eruptions Magma – hot, molten rock Lava is magma that has erupted from a volcano Lava

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 contains a 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) rocks Indians used this rock to make tools. Quartz Obsidian is often called what? “volcanic glass.” How would you describe the luster of this volcanic rock? What is this rock called?

Example of lava (volcanic) rocks Quartz Basalt 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) rock Pumice 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?

Let’s Review … There are 3 types of rocks! Igneous Sedimentary Metamorphic

Rocks are identified by … how they are formed Let’s Review …

Igneous rocks are formed when… Molten magma or lava cools and hardens. Let’s Review … Molten means …melted

Igneous means what in Greek? Fire Let’s Review … Yep!

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 inside the volcano from magma are: Granite Let’s Review … Gabbro Well done!

Some rocks that form outside of the volcano from cooled lava are: Obsidian Let’s Review … Basalt Pumice Very good!

1. What thinking map could we use to record what we know about igneous rocks?

2. What thinking map could we use to record how rocks are classified?

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

Next week we’ll learn more about sedimentary and metamorphic rocks.

Geology for Kids All about volcanos Go to our class website for this powerpoint and these web links. Good Web Links