Here's why:
* Igneous rocks are formed from the cooling and solidification of molten rock (magma or lava).
* As the molten rock cools, the minerals within it start to crystallize.
* These crystals grow and interlock with each other, forming the solid rock structure.
Examples of igneous rocks:
* Granite: A coarse-grained igneous rock with large, visible crystals.
* Basalt: A fine-grained igneous rock with small, often microscopic crystals.
* Gabbro: A dark-colored, coarse-grained igneous rock.
While sedimentary rocks can sometimes have crystals, these crystals are not the primary component of the rock's formation. Sedimentary rocks are formed from the accumulation and cementation of sediments.