Rock Facts
  • Igneous rocks are the oldest kind of rock.
  • Igneous rocks are formed deep inside the earth where the temperature is very high.
  • The minerals in the earth are in liquid form and are called magma.
  • Magma is squeezed around inside the earth and as it pushes towards the surface of the earth, it starts to cool. As it cools, it turns to solid igneous rock.
  • Sometimes the magma cools very slowly and forms rocks.
  • Igneous rocks that cool slowly deep in the earth are called Intrusive igneous rocks and have large crystals. (Granite)
  • Sometimes the magma erupts from a volcano. Magma is called lava when it reaches the earth's surface. Lava cools quickly and forms igneous rocks.
  • Igneous rocks that cool quickly on the surface of the earth form rocks with small crystals called extrusive rocks. (Basalt, obsidian) 
  • Sometimes extrusive igneous rocks look like glass and have no crystals or mineral particles.
1. Click on this website. How Igneous Rocks Are Formed and read the information about Igneous rocks
2. View the animation of the volcano exploding and the igneous rock being formed.
3. Click on the rock examples at the bottom of the web page.
4. Use this information to complete the Rocks Worksheet.
Igneous Rocks Resources

This Planet Really Rocks - Igneous Rocks

Canadian Rockhound - Igneous Rocks

All About Igneous Rocks

Igneous Rock - The Face of the Earth

 

Rock Webquest Page Igneous Rocks Sedimentary Rocks Metamorphic Rocks Rock Worksheet Name that Rock Name that Rock Worksheet The Rock Cycle Resources

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Revised: Thursday, March 27, 2008

URL: http://www.mcsdk12.org/

 

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