Types of Rocks on Earth

Introduction

Earth is made up of three types of rocks. Rocks are formed when Earth’s crust cools down and hardens into solid rock. The type of rock depends on what the molten material was made from, how much pressure it was under while cooling down and how long it took to cool down completely.

Types of Rocks

Sedimentary Rocks:

Sedimentary rocks are made of the remains of other rocks, which have been transported and deposited by water, wind or ice. They can be further classified based on their grain size, texture and composition. Some of the most common sediments include sandstone, shale and limestone.

Igneous Rocks

The rocks formed by igneous processes are called igneous rocks. These rocks are formed when molten rock cools and solidifies.

We can divide igneous rocks into two categories: intrusive and extrusive. Intrusive is any rock that forms from magma that has cooled below the surface of the Earth, while extrusive is any rock that forms from lava flows or volcanic eruptions on the Earth’s surface.

Metamorphic Rocks

You may know that igneous rocks form from magma or lava, and sedimentary rocks form when sediment settles out of the water and hardens. But do you know how metamorphic rocks get their start?

Metamorphic rocks form when extreme heat and pressure change the minerals in a rock. This can happen after an igneous or sedimentary rock has been buried deep underground for a long time. The heat and pressure can change the composition of these buried rocks so that they become harder than before, making them metamorphic!

The minerals in metamorphic rocks can be altered by being baked by volcanic eruptions or heated in hot springs (geothermal water). Sometimes this heating can cause chemical reactions between minerals to create new ones, like quartz, into mica.

Learning about rocks can be fun when you explore their different types.

Learning about rocks can be fun when you explore their different types.

• The action of water, wind and time forms rocks.
• Rocks are classified according to their chemical composition: igneous, sedimentary and metamorphic rocks.
• Rocks are classified according to their texture: coarse-grained or fine-grained rocks.
• Rocks can also be classified according to structure: extrusive or intrusive (volcanic) rocks.

Conclusion

If you’re looking for something interesting, try exploring the different types of rocks on Earth. You never know what kind of hidden gems you might find!