Igneous Rocks
Pages 150-157
Vocabulary
magma - melted rock below Earth’s surface
lava - melted rock that reaches Earth’s surface
igneous rocks - are rocks that form from melted rock
intrusive igneous rock - forms when magma cools and hardens
below the Earth’s surface
5. extrusive igneous rock - forms when lava cools and hardens above
the Earth’s surface
1.
2.
3.
4.
Facts to Know:











Igneous means “fire made”
Igneous rocks are classified by the way they are formed.
It takes a long time for magma to cool below Earth’s surface.
Large mineral crystals form when magma cools slowly.
Above the surface of Earth lava cools rather quickly.
Small mineral crystals form when lava cools quickly.
The properties of an igneous rock are determined by the way it
is formed and the minerals that make it up.
Obsidian cools so quickly it does not form mineral crystals.
Granite makes a strong long-lasting building material because of
its hardness.
Gabbro is often mixed into concrete and used to make sidewalks,
bridges, and buildings.
Pumice is put into soaps and cleansers.
Magma- melted rock
surface
below
the
surface
Lava- magma that reaches the
above
the
surface