Igneous Rocks

Which would have larger crystals, intrusive or extrusive igneous rocks

• intrusive
• extrusive

Magma forms on the surface or under the surface?

• on the surface
• under the surface

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

• granite
• basalt
• scoria
• 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

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

• coarse-grained
• fine-grained
• glassy

Rapid cooling of lava in which no crystals form results in _____ texture

• coarse-grained
• porphyritic
• glassy

Fast cooling of lava in which small crystals form results in _____ texture.

• coarse-grained
• fine-grained
• porphyritic

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

• mafic

• felsic

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

• mafic

• felsic

A slow cooling igneous rock will have _____ crystals

• large
• small
• average
• black