When molten rock (lava) crystallizes above ground, it forms extrusive igneous rock , also called volcanic rock.

Quick Scoop: The Rock Type

  • Molten rock underground = magma.
  • When magma reaches the surface, we call it lava.
  • If that lava cools and crystallizes above ground , the resulting rock is an extrusive igneous rock.
  • Common examples: basalt and many types of lava flows you see around volcanoes.

In other words, your question:

“When molten rock undergoes crystallization above ground, what type of rock results?”

Answer: Extrusive igneous rock (volcanic rock). ✅

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