Igneous (IG-nee-us) rocks form from melted rock, or magma, that comes from inside Earth. Sometimes the magma erupts from a volcano, and then cools and hardens at Earth's surface. Magma can also cool slowly and form rocks underground. Igneous rocks are brand-new rocks. They don't form from other rocks. Igneous rocks include pumice, granite and obsidian, pictured.
Sedimentary (sed-uh-MEN-tuh-ree) rocks form from tiny pieces of rock that are broken down by wind and water. Over time, these pieces settle in layers with sand, silt, dead plants, and animal skeletons. These sediments are squeezed by other sediments above them until they cement together to form a rock. Sedimentary rocks include sandstone, chalk and limestone, pictured.
Want to learn more about our the world around us? Check out Willy's Wilderness, a nature website for kids (and their parents) from the Forest Preserve District of Will County!
Map your next adventure and reconnect with nature! Visit ReconnectWithNature.Org for the latest news on where to go and what to do!
The Nature Foundation of Will County
17540 W. Laraway Rd.
Joliet, IL 60433
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