📖 what
What is igneous rock?
Quick Answer
An igneous rock forms when molten rock cools and solidifies. If it cools underground it is intrusive; if it cools at the surface it is extrusive.
The Full Story
Igneous rocks are the products of magma or lava cooling and crystallizing. Slow cooling underground makes large crystals, as in granite, while rapid cooling at the surface produces fine-grained or glassy rocks such as basalt and obsidian. These rocks make up much of Earth’s crust, especially the ocean floor. Studying their mineral crystals helps geologists understand cooling history and magma composition.
Key Facts
1.Granite is intrusive
2.Basalt is extrusive
3.Oceanic crust is mostly basaltic
YouTube Angle
Suggested video title for this topic:
"From molten rock to solid stone"
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