Molten minerals from mantle cool and harden at different rates to make rock {igneous rock}|.
Igneous-rock slow cooling makes coarse grain crystals {granite}|.
dark, hard, smooth {diorite}.
Igneous-rock rapid cooling makes fine grain crystals {obsidian}.
Rhyolite {pumice} can form with gas bubbles.
Fine-grained glassy granite {rhyolite} has color bands.
Basalt lava flows have red-brown, porous rocks {scoria} that contain gas bubbles.
Igneous rocks {sialic rock} can be mostly silicon and aluminum. Granite, continental rock, and sediments are sialic.
soft volcanic rock {tufa}.
aerated light volcanic rock {tuff}.
5-Earth Science-Mineral-Kinds-Rock
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Date Modified: 2022.0225