Which rock type forms from the cooling of magma or lava?

Which rock type forms from the cooling of magma or lava?

• A. Igneous rocks
• B. Sedimentary rocks
• C. Metamorphic rocks
• D. Mineral

Answer: (A)

Igneous rocks form from the cooling and solidification of molten rock. If magma cools slowly beneath the surface, large crystals have time to grow, as with granite. If lava erupts onto the surface and cools rapidly, the rocks become fine‑grained, like basalt or rhyolite, and sometimes glassy, like obsidian. This distinguishes igneous rocks from sedimentary rocks, which form from weathered pieces that are deposited and cemented, and from metamorphic rocks, which arise when existing rocks are altered by heat and pressure without melting. Minerals are the building blocks of rocks, not a rock type themselves.

Igneous rocks form from the cooling and solidification of molten rock. If magma cools slowly beneath the surface, large crystals have time to grow, as with granite. If lava erupts onto the surface and cools rapidly, the rocks become fine‑grained, like basalt or rhyolite, and sometimes glassy, like obsidian. This distinguishes igneous rocks from sedimentary rocks, which form from weathered pieces that are deposited and cemented, and from metamorphic rocks, which arise when existing rocks are altered by heat and pressure without melting. Minerals are the building blocks of rocks, not a rock type themselves.