* Igneous rocks are formed from the cooling and solidification of molten rock (magma or lava). They are essentially brand new rocks, formed from the Earth's internal heat and pressure.
* Metamorphic rocks are formed when existing rocks (igneous, sedimentary, or even other metamorphic rocks) are transformed by heat and pressure, but without melting completely. This means they are essentially "recycled" rocks.
Here's a table summarizing the key differences:
| Feature | Igneous Rocks | Metamorphic Rocks |
|---|---|---|
| Formation | Cooling and solidification of magma or lava | Transformation of existing rocks by heat and pressure |
| Origin | Molten rock | Existing rocks (igneous, sedimentary, or metamorphic) |
| Texture | Crystalline, glassy, or fragmental | Often foliated (layered) or non-foliated |
| Examples | Granite, basalt, obsidian | Marble, slate, gneiss |
Think of it this way:
* Igneous rocks are like newly baked bread. They are formed from a completely new process.
* Metamorphic rocks are like reheated bread. They are still bread, but their texture and taste have been changed by the heat and pressure.
