The Main Types of Rocks
How they form
These are some Igneous rocks
In the rock cycle, there are 3 main types of rocks.
- One of them is a sedimentary rock. These rock are usually have a layered look, and the layer are layer of sediment
- Another one is a metamorphic rock. It still has layers but the are now more wavy because of heat an pressure.
- the last rock is an Igneous rock. The rocks don's all look alike. Some are like obsidian, shiny, smooth, and black. While others are like granite, still shiny, but have a rough texture and a dotty look.
Igneous
an igneous rock forms when lava comes out of a volcano and cools
Sedimentary
A sedimentary rock form when over the years as sediment piles up on the ocean floor, and as the pressure increases, it all squeezes together to form a sedimentary rock
Metamorphic rock
A metamorphic rock form when a sedimentary rock goes through more pressure and gets heated, so through heat and pressure, a sedimentary rock changes into a metamorphic rock
Super fun facts
These are some sedimentary rocks
- Earth's crust is made Entirely of rock
- There has been over 700 identified igneous rocks, That's a lot!
- 95% of earth's crust is made up of Igneous rock
- Rocks have been used for millions of years! all the way back from the stone age to today
- Rocks take millions of years to form
these are Metamorphic rocks
The Rock Cycle