1. Cooling Magma: As molten magma rises towards the Earth's surface, it begins to cool down.
2. Nucleation: As the magma cools, the atoms and molecules within it start to slow down and arrange themselves into more organized structures. This process, called nucleation, starts the formation of tiny crystals.
3. Crystal Growth: Over time, more atoms and molecules join the existing crystals, causing them to grow in size. The specific minerals that form depend on the chemical composition of the magma and the cooling rate.
4. Solid Rock: As the magma continues to cool, the crystals grow and eventually become interconnected, forming a solid rock.
Types of Igneous Rocks:
The type of igneous rock formed depends on where the magma cools:
* Intrusive rocks: Formed when magma cools and solidifies beneath the Earth's surface (e.g., granite). These rocks typically have larger crystals because they cooled slowly.
* Extrusive rocks: Formed when lava (magma that has erupted onto the Earth's surface) cools and solidifies (e.g., basalt). These rocks usually have smaller crystals because they cooled quickly.
