IGNEOUS ROCKSBY CHANTAL, THIERRY, MATTHEW

What are Igneous rocks?

• Igneous rocks are rocks that are formed using volcanoes• their name is fire rocks in Latin• The magma under the earth gets ejected out of volcanoes

and lands on the cool crust which solidifies to form types of igneous rocks

• The larger the crystals are is the way of telling how fast the rock has cooled

• Large crystals would mean the rock has formed slowly while tiny or no Crystals would show that the rock has formed faster

This is a large cliff made of granite formed from volcanoes

Link to a video whe got a lot of information from: http://www.youtube.com/watch?v=mMJPVdv7D6k

Basalt Rock

The basalt rock is usually gray or black and very hard

It cools quickly (very small crystals)

It is usually extrusive but it can also be intrusive

It is the most common rock on the earths rock

There is lots of basalt on the ocean floor

It is also found on the moon and mars

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It forms when magma/lava gets out of a volcano to the surface or the ocean ridge and cools.

Intrusive: Cooled under the surfaceExtrusive: Cooled on the surface

Obsidian Rock• Obsidian Rocks are made by Nature Glass. The color of the

Obsidian Rock is made by the chemical makeup of lava.• It's a extrusive Rock because it forms on the surface.• When a Volcano erupts it spits out a lot of melted rocks.• If the rock is silica and it cools at the right temperature that is 940c-

1080c it can turn into nature glass and then it is a Obsidian Rock.• In the stone age the obsidian rock was a very good tool for knifes,

arrowheads, fishhooks etc. In surgery they still use the Obsidian Rock for knifes.

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Granite RocksGranite means granum. It is made of many quarts and feldspar bits stuck together. Granite Rocks are usually pink to gray, white or black.Granite rocks are hard stones because it was made underground andit cools underground. So it is a intrusive rock. Over millions of years allthose granite rocks build together a big crystal.

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Questions ?