Types of Metamorphic Rocks
What is Foliation, and Why Does it Happen?
There are a few different types of Foliated Metamorphic Rocks:
- Slate – Slate forms when there is low heat and low pressure. It’s very smooth and usually aligns parallel to itself. It is also very useful, we use it today for pool tables and roofs!
- Phyllite – Phyllite forms when there is low to medium heat and pressure. It has a crystallized appearance, making it look shiny. The layers in Phyllite rocks are much wavier than Slate.
- Schist – Schist forms when there is medium to high heat and pressure. These have larger crystals that align with the other layers in the rock.
Gneiss – Gneiss (pronounced nice!) is created when there is extremely high heat. It looks very grainy and has alternating light and dark minerals in it.
What are Non-Foliated Rocks? What’s the difference?
- Quartzite – Quartzite has both quartz and sandstone in it. It’s used for roofing, stair steps, and flooring.
Other Great Resources:
Non-Foliated Metamorphic Rocks – Minerology4Kids: http://www.mineralogy4kids.org/rock-cycle/nonfoliated-metamorphic-rocks
Foliated Metamorphic Rocks – Minerology4Kids: http://www.mineralogy4kids.org/rock-cycle/foliated-metamorphic-rocks
Metamorphic Rocks – SimpleWikipedia: https://simple.wikipedia.org/wiki/Metamorphic_rock
Metamorphic Rock Facts: http://www.softschools.com/facts/rocks/metamorphic_rocks_facts/366/