1. Igneous Rock Cycle
Igneous rocks are formed as magma from below the earth’s crust cools and hardens.

2. Igneous Rock Formation
Cooling may occur deep beneath the earth’s crust forming intrusive igneous rock.
Cooling may be rapid at or near the surface forming extrusive igneous rocks.

3. Igneous Rock Formation
Slow cooling produces rocks with large grains.
Intrusive: large grains.
Fast cooling produces smaller, often unnoticeable grains.
Extrusive: smaller grains
Rocks can begin to cool slowly and then rapid cool
Porphyry: combo grains

4. Families of Igneous Rocks
Felsic rocks are formed from magma called felsic – high in silica (SiO2)
Mafic rocks are formed from mafic magma – low in silica
Ultramafic rocks are made up of a combination of the minerals in both felsic and mafic magma.