Metamorphic Rock

geology · earth · transformation · pressure

Extreme heat required. Metamorphic rocks form when existing rocks are heated to more than 150 to 200 degrees Celsius (that's hot enough to bake bread many times over) deep underground.

Crushing pressure too. The rocks also experience massive pressure of 100 megapascals or more, which is like having thousands of elephants standing on top of you.

Stays solid the whole time. Unlike melting, the rock never turns into liquid during metamorphism, but its minerals rearrange and recrystallize into a brand new composition and texture.

Any rock can transform. The starting rock (called the protolith) can be igneous, sedimentary, or even another metamorphic rock that gets cooked and squeezed all over again.