Here's why:
* Metamorphism is a process where existing rocks are transformed by heat, pressure, and/or chemically active fluids.
* Igneous rocks formed from cooling magma or lava can be transformed into metamorphic rocks like marble (from limestone) or schist (from shale).
* Sedimentary rocks like sandstone and limestone can also undergo metamorphism, becoming quartzite and marble respectively.
* Other metamorphic rocks can be further metamorphosed into different types, experiencing changes in mineral composition, texture, and sometimes even chemical composition.
In short, any existing rock can become metamorphic if subjected to the right conditions. The specific type of metamorphic rock that forms depends on the original rock type, the intensity of heat and pressure, and the presence of fluids.
