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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 (ignite, ignition)
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
Coarse- roughFine - smooth
Intrusive/Inside • 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
Granite(Intrusive)
Coarse Grained 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
Intrusive
Extrusive
• Igneous rock formed from lava that has flowed out onto the Earth’s surface.
• Solidifies fast• Cools rapidly• Small/fine grains• Ex-basalt/obsidian• Can’t see the crystals
• http://library.thinkquest.org/J002289/rocks.html
Name of Rock Basalt Granite
Type of Igneous extrusive intrusive
Texture Glassy or fine Course,rough
Crystals Small crystals Large Crystals