The Rock Cycle

What is the rock cycle?
The rock cycle is a conceptual model used to understand geological processes surrounding the lifecycle of the Earth's rocks.

How does it work?
There are three basic categories used to classify rocks:
Igneous - These rocks are formed as magma, or molten rock cools and becomes a solid.
Sedementary - Created as the eroded particles of other rocks congeal together.
Metamorphic - Under extreme temperature and pressure, other rocks are forced to change their composition into this form of rock.
Each of these types of rock can become any of the other types through a few very simple processes:
Melting - Over time all rocks will eventually melt to create magma which will find its way out from beneath the surface forming igneous rock again.
Weathering and Erosion - All rock exposed to the elements are subject to these forces, which over time create sedementary rock.
Temperature and Pressure - As rock is squeezed together the forces acting upon it actually serve to change its chemical make up into metamorphic rock.

Artwork by Maija Swanson and Nick Olejniczak