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Different types of rock

There are many different types of rocks in the world.

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Identifying rocks

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Identifying rocks: summary

sedimentary

metamorphic

igneous

sandstone and limestone

marble and slate

basalt and granite

the softest rock type, containing layers and sometimes fossils

usually harder than sedimentary rocks, containing thin layers and twisted fossils

usually the hardest rock type, containing shiny crystals

type examples description

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Different rocks = different uses

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Formation of sedimentary rocks

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Formation of metamorphic rocks

Sedimentary rocks are turned into metamorphic rocks by the extreme pressures and temperatures deep within the Earth.

These conditions change the structure of the rocks so that new layers are formed.

Heat and pressure compress grains

Grains form orderly layers

Mixture of grains in structure

pressure

heat

more pressure

more heat

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Formation of igneous rock

Magma is a type of molten rock found deep underground. Occasionally magma rises up through the Earth’s surface, causing volcanic eruptions.

When magma cools above the surface, extrusive igneous rocks are formed.

Igneous rocks are formed when the magma cools and solidifies.

When magma cools below the surface, intrusive igneous rocks are formed.

extrusive igneous

rock

intrusive igneous

rock

magma

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Crystal size in igneous rocks

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The rock cycle

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The rock cycle: in words

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The rock cycle: summary

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From weathering to sedimentation