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Science
Earth Science
Geology
Minerals and Rocks
Rocks
What Are the Three Main Rock Groups?
Igneous Rocks
How Are Igneous Rocks Formed?
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Explanations
1
Formation of Igneous Rocks Igneous Rocks, also known as "rocks of fire," are formed by the hardening of magma or lava. Therefore, rocks formed by magma hardening inside of Earth…
By Nina Jiang
Problems
2
Indicate what rock type is being described: Obsidian is smooth, black, and glass because it cooled so quickly.
Indicate what rock type is being described: by cooling slowly, large crystals could form.
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