Types of Rocks and the Rock Cycle

• Geologists study rocks to learn about Earth's history.
• Sedimentary rocks form from layers of sediment.
• Igneous rocks form from volcanoes.
• Metamorphic rocks form from heat and pressure.
• A rock's physical characteristics come from the way it was formed.
• A rock is a solid piece of the Earth's surface made of one or more minerals.
• A mineral is a natural solid found on Earth's surface that is not plant or animal.
• The processes by which rocks change into new rocks make up the rock cycle.
• Weathering, deposition, compaction, and cementation form sedimentary rock.
• Changing from one rock type to another takes millions of years, which gives scientists clues to the past environment where that rock formed.
• Igneous rocks form from magma.
• When magma erupts from a volcano or comes to the surface, it is known as lava.
• Granite is an example of an igneous rock that forms below the surface.
• Pumice is a rock that is so light it can float on water.
• Sedimentary rocks form from sediment.
• Surface forces break down rocks in a process called weathering.
• Metamorphic rocks form from heat and pressure.
• Fossils form in Sedimentary rock
• Compression is when minerals gradually replace the organism's tissue.
• A paleontologist is a scientist who studies fossils.

Explore the formation and characteristics of sedimentary, igneous, and metamorphic rocks. Understand the rock cycle, including weathering, deposition, and the transformation processes that occur over millions of years. Learn how rock formations offer clues about Earth's past environments.