**Extrusive and Intrusive Rocks Formation**
Extrusive and intrusive rocks are two types of igneous rocks that are formed through different processes. The formation of these rocks is related to the movement and cooling of molten rock, or magma.

**Extrusive Rocks**
Extrusive rocks, also known as volcanic rocks, are formed from magma that reaches the Earth's surface and cools rapidly. This rapid cooling prevents the formation of large crystals, resulting in a fine-grained texture. Here is the process of extrusive rock formation:

1. **Magma Formation**: Magma is formed in the Earth's mantle through the melting of rocks due to high temperatures and pressure.
2. **Magma Rise**: Magma rises towards the Earth's surface through cracks and fractures in the Earth's crust, driven by the buoyancy of the molten rock.
3. **Volcanic Eruption**: When the magma reaches the surface, it erupts from a volcano in the form of lava, ash, and gases.
4. **Rapid Cooling**: As the magma is exposed to the cooler atmospheric conditions, it rapidly cools down and solidifies, forming extrusive rocks.
5. **Fine-Grained Texture**: Due to the rapid cooling, the crystals in extrusive rocks are too small to be seen by the naked eye, giving them a fine-grained texture.

Examples of extrusive rocks include basalt, obsidian, and pumice.

**Intrusive Rocks**
Intrusive rocks, also known as plutonic rocks, are formed when magma cools slowly beneath the Earth's surface. This slow cooling allows the crystals to grow larger, resulting in a coarse-grained texture. Here is the process of intrusive rock formation:

1. **Magma Formation**: Similar to extrusive rocks, magma is formed in the Earth's mantle through the melting of rocks.
2. **Magma Intrusion**: Instead of reaching the surface, the magma remains trapped beneath the Earth's surface in magma chambers or pockets.
3. **Slow Cooling**: As the magma is insulated by the surrounding rocks, it cools slowly over a long period of time.
4. **Large Crystals Formation**: The slow cooling allows the crystals to grow larger, resulting in a coarse-grained texture.
5. **Exposure through Erosion**: Over time, the overlying rocks are eroded away, exposing the intrusive rocks at the Earth's surface.

Examples of intrusive rocks include granite, diorite, and gabbro.

**Conclusion**
Extrusive and intrusive rocks are formed through the cooling of magma, but the rate of cooling and location of solidification determine their texture and appearance. Extrusive rocks cool rapidly on the Earth's surface, resulting in fine-grained textures, while intrusive rocks cool slowly beneath the Earth's surface, leading to coarse-grained textures.

Extrusive rocks formed when molten magma comes on the earth 's surface and it rapidly cools down and became solid .


Intrusive rocks formed when molten magma cools down deep inside the earth 's crustand became solid . These rocks cools down slowly.