However, it's important to note that quartz itself is actually a mineral, not a rock. It is a very common mineral that can be found in many different types of rocks, including:

* Igneous rocks: Quartz is a common component of granite, rhyolite, and other felsic igneous rocks.

* Metamorphic rocks: Quartz can also be found in metamorphic rocks like quartzite, which is formed by the metamorphism of sandstone.

* Sedimentary rocks: Quartz is a major component of sandstone and some other sedimentary rocks.

So, while quartz can be found in igneous rocks, it is not exclusive to them and can exist in other rock types as well.