Go Deeper For parents & teachers
The most common extrusive igneous rock on Earth, formed when low-silica lava cools rapidly. Basalt is fine-grained because crystals don't have time to grow large, and it's usually dark because of its iron and magnesium content. Ocean crust is overwhelmingly basaltic; continental flood basalts like the Deccan Traps in India and the Columbia River Basalts in the US cover enormous areas on land and are associated with some of Earth's largest extinction events.
Appears In
The Burning Mountain Chapter 1 — When the Mountain Roared
"The path curved around a rib of dark basalt and entered the narrowest section, where a low wall guarded one side and …"
The Burning Mountain Chapter 4 — The Warning Station
""We need the central display on the sheltered side," Monty said, eyeing the basalt rib."
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