Igneous Rocks

Which terms best describe igneous rocks?

• light and easily broken
• soft and smooth
• hard and dense
• soft and dense

_____ is an igneous rock made up of the minerals quartz, mica, feldspar, and hornblende.

• granite
• basalt
• pumice
• gneiss

How do coarse-grained igneous rocks form?

• from sedimentary rocks changed under pressure
• from large rock particles cemented together
• from rapidly cooling lava
• from slowly cooling magma

Which igneous rock is an extrusive rock?

• porphyry
• rhyolite
• pegmatite
• granite

Slow cooling magma far beneath Earth's surface results in _____ texture.

• coarse-grained
• fine-grained
• glassy

Rapid cooling of lava in which tiny crystals form results in _____ texture

• coarse-grained
• fine-grained
• glassy

Extremely rapid cooling of lava in which no crystals form results in _____ texture.

• coarse-grained
• fine-grained
• glassy

What is the most common type of extrusive rock?

• basalt
• granite
• obsidian
• porphyry

Igneous rock that formed when magma hardened beneath the surface of Earth is called _____ rock

• intrusive
• extrusive
• clastic
• silica

Lava that is low in silica usually forms _____ colored rocks.

• dark
• light