Granite (Igneous)
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In plain terms
Granite is a slow-cooled rock made of interlocking crystals—often quartz + feldspar + mica.
How it forms
Granite forms when silica-rich magma cools slowly within the crust. Slow cooling allows large crystals to grow, creating a coarse, “salt-and-pepper” texture (often with pink or white feldspar and clear/gray quartz).
What to look for
- Visible interlocking crystals (coarse-grained)
- Quartz (glassy, gray/clear), feldspar (white/pink), mica (black/silvery flakes)
- Generally hard and durable; scratches glass
Key takeaways
- Coarse crystals = slow cooling underground.
- Quartz + feldspar are common components.
- Granite is widespread in continental crust.
- Weathering can highlight feldspar and mica.
- Context (plutons, batholiths) supports identification.