Here's why:
* Metamorphic rocks are formed when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are subjected to intense heat and pressure deep within the Earth's crust or mantle.
* The heat and pressure cause the minerals in the original rock to recrystallize and change their structure, resulting in a new rock type with different properties.
Examples of metamorphic rocks:
* Marble: Formed from limestone
* Slate: Formed from shale
* Gneiss: Formed from granite or other metamorphic rocks
While some igneous rocks can form deep underground (like granite), they can also form on the surface (like basalt). Sedimentary rocks, on the other hand, form at the Earth's surface from sediments.
