Igneous Rocks

Front

True or False. Igneous rocks ( like the basalt shown here) are classified by their origin, texture, and mineral composition.

Back

True

Front

___________ rock is igneous rock formed from lava that erupted onto Earth's surface.

Back

extrusive

Front

Igneous rock that formed when magma hardened beneath the surface of Earth is called ___________ rock, like this granite wall that formed underground millions or even billions of years ago.

Back

intrusive

Front

True or False. Different igneous rocks may have similar mineral compositions and yet have very different textures depending on how fast they cooled. (Like this obsidian which is glassy because it cooled quickly.)

Back

True

Front

Magma that is _______ in silica content forms light-colored rocks such as granite.

Back

high

Front

Lava that is _________ in silica usually forms dark-colored rocks such as basalt.

Back

low

Front

True or False. Slowly cooling lava forms fine-grained igneous rocks with small crystals or no crystals at all like this pumice.

Back

True

Front

Where would molten rock cool more quickly, on Earth's surface or beneath the surface?

Back

on Earth's surface

Front

True or False. Igneous rocks are used for tools and building materials.

Back

True

Front

Igneous rocks were once melted rock. (lava or magma)

Back

True