Here's why:
* Intrusive rocks are formed when magma (molten rock) cools and solidifies beneath the Earth's surface.
* The magma forces its way into existing rock layers, creating intrusions like batholiths, dikes, sills, and laccoliths.
* Since they cool slowly underground, they have time to develop large crystals, giving them a coarse-grained texture.
Examples of intrusive rocks: granite, diorite, gabbro
In contrast, extrusive rocks are formed when lava (magma that erupts onto the surface) cools and solidifies. These rocks have a fine-grained texture due to rapid cooling.
Examples of extrusive rocks: basalt, rhyolite, andesite
