Igneous Rock vs Metamorphic Rock — Difference (with Table & FAQs)
Igneous Rock vs Metamorphic Rock compared side by side — a 5-row comparison table, 4 key points and 3 exam FAQs. Class 7-9 Science, free and no sign-up.
TL;DR: Igneous Rock vs Metamorphic Rock compared side by side — a 5-row comparison table, 4 key points and 3 exam FAQs. Class 7-9 Science, free and no sign-u…
Written & reviewed by the Syllab.in Academic Team (CBSE/NCERT subject experts) · Updated
The main difference between Igneous Rock and Metamorphic Rock: Igneous rock forms from cooling and solidification of magma or lava. Metamorphic rock forms when existing rock is changed by heat, pressure, and chemical p
Igneous Rock vs Metamorphic Rock — Comparison Table
| Basis | Igneous Rock | Metamorphic Rock |
|---|---|---|
| Formation | Cooling of magma or lava | Change of existing rock by heat and pressure |
| Temperature | Very high, molten origin | High pressure and temperature, below melting |
| Crystal Size | Depends on cooling rate: large or small | Interlocking crystals from recrystallization |
| Examples | Granite, basalt, obsidian | Marble, slate, schist |
| Parent Rock | None, forms from magma | Any existing rock can be metamorphosed |
Key Points
- Igneous rocks form from cooling magma or lava
- Metamorphic rocks form from existing rocks changed by heat and pressure
- Igneous rocks cool from a molten state while metamorphic rocks form in solid state
- Both are important parts of the rock cycle
Frequently Asked Questions
What is the difference between igneous and metamorphic rock?
Igneous rock forms when molten magma or lava cools and solidifies. Metamorphic rock forms when an already existing rock is altered in the solid state by heat and pressure — it never fully melts.
Why do some igneous rocks have large crystals and others none?
It depends on cooling rate. Magma cooling slowly deep underground gives crystals time to grow large, as in granite. Lava cooling quickly at the surface leaves crystals too small to see, as in basalt.
Are igneous rocks the oldest rocks?
Igneous rock is the original source of the material in the other two types, since weathered igneous rock supplies sediment. But rocks cycle continuously, so an individual igneous rock is not necessarily older than a nearby sedimentary or metamorphic one.