* Intrusive (Plutonic) Igneous Rock: These rocks form when magma cools and crystallizes slowly beneath the Earth's surface. They tend to have large crystals due to the slow cooling process. Examples include granite, gabbro, and diorite.
* Extrusive (Volcanic) Igneous Rock: These rocks form when lava erupts onto the Earth's surface and cools rapidly. They typically have small crystals or are glassy due to the quick cooling. Examples include basalt, rhyolite, and obsidian.
* Ultramafic Igneous Rock: This type of rock is characterized by its high magnesium and iron content. It typically forms from deep within the Earth's mantle and is very dense. Examples include peridotite and dunite.
