The Rock Cycle

Stephen Liang

The Rock Cycle

The rock cycle is a never-ending process in which one rock of its specific type is geologically altered (i.e. heat and pressure) by some means and becomes another rock of another type. The rock cycle explains that Granite, an igneous rock, can become Gneiss, a metamorphic rock, by being heated and compressed.
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About Rocks

Granite- An Igneous Rock

Granite

Granite is an igneous rock. Granite cools intrusively and is the most common rock in the continental plates of Earth. It is felsic, meaning it is composed highly of quartz. In fact, the main chemical that granite is composed of is quartz.


Igneous Rocks

Igneous rocks are formed by lava or magma hardening. Since lava is above the surface of the earth and magma rests below the surface, extrusive refers to lava cooling and intrusive refers to magma cooling. Granite is intrusive. They are classified as sometimes having glassy textures (Obsidian), sometimes porous (Pumice), and maybe coarse-grained (Granite). Igneous rocks are found near volcanoes because they were formed from hardening magma or lava.


Igneous rock photos

Sandstone- A Sedimentary Rock

Sandstone

Sandstone is a clastic sedimentary rock made from vast amounts of Quartz and feldspar. Since sandstone is so similar to sand, the color varies with the regions. Sandstone is very common throughout the world where there is sand. It can be used to build stonemasonry. In the western part of the US, you can see sandstone formations, like in Antelope Canyon, Arizona.


Sedimentary Rocks

Sedimentary rocks are formed by the compaction of sediments (Eroded Rock Material). Sometimes, rocks move into the ocean. The gigantic water movements push on the rock, eroding it to sediment. After that, more sediment is pushed on, making the sediments into one rock. The final process mentioned here is called compaction. Sedimentary rocks are found in places where there has been water once. Sedimentary rocks are classified by their rough texture and the feel that sediments are falling off everytime you touch it. Sedimentary rock is not hard; pieces will fall off when you hit it.

Gneiss- A Metamorphic Rock

Gneiss

Gneiss is a metamorphic rock that is usually formed from granite being heated and compressed. Common chemicals in gneiss are : quartz and feldspar. It is composed of many layers. Gneiss makes up the largest part of the Earth's lower crust. If you watch a gneiss closely, you will notice that it is made from layers.


Metamorphic Rocks

Metamorphic rocks are rocks that have gone through extreme heat and pressure. That process makes the rock change its structure. It classified as having ribbonlike layers (Gneiss) and may have shiny crystals (Quartzite). It is found at the roots of mountains.