Rocks
By: Jordan K. Worley
The Trio
Each rock group has a unique type of formation, which is how their class if defined.
Sedimentary
Mostly on the earths upper crust, a few meters under ground, or under an ocean, a place with moderate pressure.
Breccia is an example of a sedimentary rock, it is formed by compaction and cementation of various rocks.
it is inorganic, mostly quartz, feldspar, and clay minerals, it contains other rock fragments.
Igneous
Intrusive rocks form inside of volcanoes, and have larger crystals, than their extrusive cousins, who form outside of the volcanoes.
These rocks can be found on the surface, and under the upper crust, Igneous rocks will form where ever there is magma / lava provided they are allowed to cool into a solid state.
Granite is an example of a igneous rock, it's a intrusive igneous rock meaning it is formed within a volcanoes, granite naturally has larger crystals because it's intrusive and has longer to cool.
granite has an average crystal size of 1 mm or larger, granite is coarse, granite is usually lighter in color and is non-vesicular.
v
Metamorphic
Because of these requirements, Igneous rocks have a signiture banding like pattern, this helps identify metamorphic rocks from igneous rocks.
Phyllite is a example of a metamorphic rock, it has the typical banding pattern associated with metamorphic rocks,
It has a fine to medium grain size, and has mineral alignment, also foliated. it is composed of Mica Quartz, Feldspar, Amphibole, garnet, and pyroxene.