Rocks Review

Magma that is low in silica usually forms light-colored rocks, such as granite.

• True

• False

How do coarse-grained intrusive igneous rocks form?

• from sedimentary rocks changed under pressure

• from large rock particles cemented together

• from rapidly cooling lava

• from slow cooling magma

Igneous rocks are classified by their origin, texture, and mineral composition.

• True

• False

Extrusive rocks have larger grains than intrusive rocks.

• True

• False

When all the grains in a rock are large and easy to see, the rock is described as

• Fine-grained

• Coarse-Grained

• Glassy

An igneous rock commonly used as building material is

• Slate

• Sandstone

• Granite

An igneous rock that is formed from lava is called an

• Extrusive

• Intrusive

The slower magma cools, the smaller the mineral crystals form.

• True

• False

Extremely rapid cooling of lava in which no crystals form, creates what type of texture?

• Fine-Grained

• Coarse-Grained

• Glassy

High silica content in magma=

• Darker-colored rock

• Lighter-colored rock