1. Larger Crystal Size:
* Intrusive rocks cool slowly underground. This allows minerals to grow larger crystals, giving the rock a coarse-grained texture. Think of granite with its visible speckles of quartz, feldspar, and mica.
2. No Vesicles:
* Intrusive rocks don't have holes (vesicles). This is because they don't erupt onto the surface and escape gases as extrusive rocks do.
3. Often Contain Xenoliths:
* Intrusive rocks may have xenoliths, which are fragments of surrounding rock. These get incorporated into the magma as it rises through the Earth's crust.
4. Found in Plutons:
* Intrusive rocks form underground in large masses called plutons. These can be batholiths, stocks, sills, or dikes.
5. Examples:
* Granite, gabbro, diorite, and peridotite are examples of intrusive igneous rocks.
In contrast, extrusive rocks cool quickly on the surface and have:
* Fine-grained textures (like basalt) or glassy textures (like obsidian).
* Vesicles (like pumice).
Let me know if you'd like more details about any of these characteristics!
