...you have never seen rocks in depth like this in your life
by David Mosca
What is a rock?
A rock is made by a composition of minerals. Rocks can be classified into three types: Igneous, Sedimentary, and Metamorphic.
Example Of An Igneous Rock - Gabbro
Gabbro is an intrusive igneous rock, meaning that the rock was formed inside of a volcano. The crystal size on Gabbro vary between 1mm to 10mm, depending on how fast it solidifies and the texture of Gabbro is very coarse, or rough. Gabbro is a non vesicular rock, or it does not have holes in it. The color of Gabbro is very dark, and Gabbro's density is very high. Gabbro's composition is mafic, meaning its rich in Magnesium and Iron. Many minerals make up the composition of Gabbro. 26% of Gabbro is Plagioclase Feldspar, 63% is Pyroxine, and 11% is Olivine.
Example of a Sedimentary Rock - Sandstone
Sandstone is a inorganic sedimentary rock, meaning it was formed from sediments of other rocks. The texture of Sandstone is clastic, or fragmental, and the grain size is about .006 cm to .2 cm. Sandstone's composition is made mostly of quartz, feldspar, and clay minerals. Sandstone also varies from fine to coarse.
Example of a Metamorphic Rock - Schist
Shist is a foliated metamorphic rock, meaning that it's mineral alignment has a pattern of some sort. Schist's grain size is fine to medium grains. The composition mostly contains Mica, Quartz, Feldspar, Amphibole, Garnet and a little bit of Pyroxene. The type of Metamorphism, or change for a rock to transform into a metamorphic rock, was a Regional Metamorphism, or a metamorphism where heat and pressure increases. Schist also has platy mica crystals that are visible from metamorphism of clay or feldspar.
The Rock Cycle:
The Rock Cycle is a model showing how rocks and sediments change over time. There are two types of processes that occur during a rock cycle: External Processes and Internal Processes. External processes occur on Earth's surface from weathering and erosion, and Internal Processes occurs within the Earth.