Download All rocks on Earth were initially igneous.Igneous rocks form as liquid

What are igneous rocks?
All rocks on Earth were initially igneous.
Igneous rocks form as liquid magma cools,
forming crystal structured rocks.
There are many different types of igneous
rocks.
Ignis means fire
Where do they form?
Either deep within Earth or
on Earth’s surface.
http://library.thinkquest.org/05aug/00461/igneous.htm
Two Types of Igneous Rocks
• Scientists divide igneous rocks into two
different categories.
• Those which were cooled below the
surface are called intrusive rocks
• Those which cooled on the surface are
referred to as extrusive rocks.
Igneous Rocks- Word Connections
Extrusive- Exit,
Exoskeleton,exterior
Intrusive-inside,
intrude,interior
Granite(Intrusive)
Intrusive/Inside
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most common -intrusive igneous
rocks.
forms when a pocket of magma
slowly cools down
Turns into solid rock beneath
earth’s surface
Coarse/large grain crystals
You can see the crystals
If you look closely at a piece
of granite you will see little
flecks of white, black, gray,
and sometimes pink. These
flecks of color are crystals
Coarse Grained Crystals
Extrusive
• Igneous rock formed from lava that has
flowed out onto the Earth’s surface.
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Solidifies fast
Cools rapidly
Small/fine grains
Ex-basalt/obsidian
Can’t see the crystals
• http://library.thinkquest.org/J002289/rocks.
html
Extrusive
Obsidian(Volcanic Glass)
extrusive
intrusive
Glassy or fine
Course,rough
Small crystals
Large Crystals
Careers in Science
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Petraologists study igneous rocks
Field observations
Laboratory studies
Geochemical analyses and experiments