Rock Classification & Cycle

The Igneous rock forms by the melting and cooling of magma. To classify the igneous rock you can describe it as mafic, which is darker and denser. Or as felsic which is lighter colored and less dense. Some igneous rocks are formed by magma, so they are instrusive and their crystals are larger. But other igneous rocks are formed by lava so they are extrustive and have smaller crystals so not all of them look the same. But they are all formed the same way so they all look simaller. The first picture below is of marble, and the second is basalt but they both are igneous.

Sedimentary rocks are formed like this; 1. Weathering 2. erosion 3. Deposition 4. Bury 5. compact 6. cement. They can be classified into two different groups, clastic and nonclastic. Clastic means that it is made up of rock fragments. the characteristics include layers, often has fossils in them, has lots of color, and more.

Metamorphic rocks are formed with high heat and lots of pressure. You can classify rocks by foliated or nonfoliated. This means if the crystals are formed in bands or not. Some times the rock looks like it formed in bands but it didn't and this is called false foliation. Metamorphic rocks rarely have fossils and lots of time the crystals form into bands. The second picture is marble.

Igneous rocks become sedimentary rocks when the igneous rocks rises to the surface and begins to go through the process of weather, earosion, deposition, compaction and seementaion. Igneous rocks become metamorphic rocks when after the go through the process to become a sedimentary rock they go through heat and pressure. An example of this would be when Metamorphic rocks become igneous rocks with the melting and cooling of magma and then to make sedimentary rocks they come to the surface and go through weathering, erosion, deposition, compaction and cementation. Sedimentary rocks can become igneous rocks after they melt and cool with magma. Sedimentary rocks can become metamorphic rocks after lots of heat and pressure. An example of this would be shale turning into slate.

Igneous rocks can be found on current or old volcanos. Most metamorphic rocks can be found in mountain ranges. Sedimentary rocks can be found at the bottom of lakes or oceans, because they are compacted underneath everything.

We still use rocks toaday for every day things. we use marble which is a metamorphic rock for countertops.

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