Geology hub
Igneous
How magma becomes rock: chemistry, cooling rate, texture, and what igneous rocks reveal about Earth’s interior.
Subtopics
Basalt
Fine-grained, dark volcanic rock—what it says about mantle melting, eruptions, and oceanic crust.
Granite
Coarse-grained intrusive rock—how slow cooling builds crystals and why granite is common in continents.
Obsidian
Volcanic glass—why it forms, how it fractures, and what hydration can tell us about surface exposure.
Igneous textures
From glassy to porphyritic: how texture records cooling history and eruption style.