Yes, metamorphic rocks form from existing rocks, whether they are igneous, sedimentary, or even other metamorphic rocks!

Here's how it works:

* Heat and pressure: The key ingredients for turning existing rocks into metamorphic rocks are intense heat and pressure. These conditions can arise deep within the Earth's crust, near volcanic activity, or through tectonic plate collisions.

* Changes in mineral composition: The heat and pressure cause the minerals within the original rock to recrystallize and change their arrangement. This results in a new rock with a different texture, mineral composition, and sometimes even a different chemical composition.

* No melting: It's important to note that metamorphic rocks don't melt completely. If they did, they would become igneous rocks instead. The minerals within the original rock simply change their form and arrangement under intense conditions.

Here are some examples of metamorphic rocks and their "parent" rocks:

* Marble forms from limestone (sedimentary rock)

* Slate forms from shale (sedimentary rock)

* Gneiss can form from granite (igneous rock) or other metamorphic rocks

* Quartzite forms from sandstone (sedimentary rock)

So, the next time you see a metamorphic rock, remember that it has a fascinating story to tell about its journey from one type of rock to another!