Become a backyard geologist—in one week
National Geographic's Wonder Lessons will teach you how to navigate the stars, spot cloud types, recognize common trees, and identify different kinds of rocks. Today, we’re learning about metamorphic rocks.
If you like the deepest and oldest mysteries, find a metamorphic rock. These rocks form deep within the Earth under extreme conditions. Take any rock, subject it to great heat, pressure, or chemical reactions, and it turns into something completely different. Granite can become gneiss, for example, while limestone transforms into marble.
The Appalachian and Rocky Mountains contain metamorphic rocks with strange names, like amphibolites and phyllites, and more common ones, like schist and slate. These rocks were squeezed by continental collisions, baked by volcanic intrusions, or doused with hydrothermal fluids—and sometimes all three.
Want to experience more wonder? National Geographic’s Wonder Listfeatures playful prompts and activities that turn everyday moments into wonder-filled discoveries—for families, anywhere, every day.
Illustrations by: Matt Twombly
Interactive by: JoElla Carman
