1. Igneous, Metamorphic and Sedimentary
Rock Classification
Igneous, Metamorphic and Sedimentary

2. Igneous Rocks
The word Igneous comes from the Latin word ignis which means fire
Igneous rocks come from magma

3. Magma formation There are three different ways that magma can form
A change in
Temperature
Pressure
Composition

4. A change in temperature
When the temperature of an area rises it can cause a rock to melt into magma

5. A change in pressure
If a rock heats up and rises pressure is released allowing the rock to melt into a liquid
This is what happens when a rock rises from the center of the Earth moves closer to the crust
**Remember the inner core is solid because of all the pressure

6. A change in composition
If a fluid is combined with a rock it may lower the rocks melting point . Then the rock melts into magma
We lower the boiling point of water when we add salt to it for Mac n Cheese

7. Felsic vs Mafic rocks
Felsic rocks are light colored and have a lower density
Mafic rocks are darker colored and have a higher density

8. Coarse grained vs Fine Grained
Coarse grained rocks are formed when magma cools over long periods of time. The crystals have more time to grow
Fine grained rocks cool quickly and the crystals don’t have a long time to grow

9. Intrusive Igneous Rocks
Formed inside the crust of the Earth
Usually coarse grained because the crust insulates the rock and allows it to cool slowly

10. Extrusive Igneous Rocks
Rocks that form when magma erupts onto the Earth’s surface
These rocks usually have fine or no crystals because the lava cools quickly