This model separates molten material, loose sediment and the three broad rock groups. Metamorphism changes solid rock; melting creates magma that may later crystallise as igneous rock. Some sedimentary rocks form chemically or from biological material, so compacted fragments are only one sedimentary pathway.
Earth and geology · Discover & try
Can one kind of rock become another?
Reading level 5 of 5 · AdvancedChange
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Igneous
Formed when molten rock solidifies.
Sediment
Loose material such as grains or fragments.
Metamorphism
Changes to existing rock while it remains solid.
Cementation
Minerals binding sediment grains together.
Know the materials before you choose a route
Igneous rock
Molten material cools and solidifies. Magma is molten rock below the surface.
Sedimentary rock
Loose sediment can compact and become cemented together. Some sedimentary rocks form in other ways.
Metamorphic rock
Existing rock changes under conditions such as heat and pressure while staying solid. Melting makes magma instead.
There is no compulsory loop. Choose a starting material and process, then follow one possible change.
Watch · Try · Explain
See how it works
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Selected transformations; arrows represent processes, not a fixed order or the time required.
What to look for
- Choose more than one possible path from the same rock.
- Keep melting separate from metamorphism.
- Notice that sediment and magma are not themselves solid rock types.
Explain what you noticed
What distinguishes metamorphism from melting?
Keep this idea: Earth materials follow many possible transformations, rather than one compulsory rock-cycle loop.
Follow the sources
- National Park Service — How Rocks are Classified
- U.S. Geological Survey — What are metamorphic rocks?
- National Park Service — Rocks and Minerals
Source material checked 2026-10-28. Explanations and activities by Nepedia. Agency source links do not imply endorsement.
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