TYPES OF ROCKS

HOW ARE ROCKS CLASSIFIED?

• Mineral composition: this is what minerals the rock(s) are made up of.
• Texture: this is what the rocks feel like. An example is coarse grained co paired to fine grained rocks.

Igneous rocks:
They are formed by lava and heat. When it cools, it becomes a rock.

Types of Igneous rocks:
There is 2 types of igneous rocks, intrusive and extrusive. Intrusive rocks form in underground chambers which lava forms the rocks. Extrusive rocks are formed when lava erupts and rocks form above ground. An example of intrusive igneous rocks is a diorite. An example of extrusive is basalt.

Sedimentary rocks:
These rocks form from weathering (when natural weather wears off the rocks), erosion (when water forms rocks), deposition (when rocks are added to a landmass), burial (when rocks get sent underground), and cementation (the hardening and welding of rocks).

Types of sedimentary rocks:
Clastic which is when sediments are buried, and cemented together by calcite or Quartz. Chemical sedimentary rocks form when water evaporates. Organic sedimentary rocks form from fossils.

Metamorphic rocks
This rock forms when exposed to high temperature and pressure.

Metamorphic rocks
There is 2 types of metamorphic rocks: foliated (this is when metal grains are arranged into planes or bands. An example is slate.), and unfoliated (which is when they don't have mineral grains aligned. An example is marble).