Metamorphic rocks are formed from igneous and sedimentary rocks that have been changed in some way by heat or pressure inside the Earth. The elements that make up the rocks may be remixed, but no new ones are added or old ones taken away. Marble, for example, is a ‘changed’ form of limestone.
Meta is Greek for change. Morphe means form.
So, metamorphosis is just a big word to mean “big change of shape”.
Geologists classify rocks into three types according to the different ways in which they’re formed:
- Igneous (pronounced ig-knee-us)
- Metamorphic (met-a-more-fic)
- Sedimentary (sed-ee-ment-ary)