Igneous Rocks

Front

What is an igneous rock?

Back

Igneous rocks are formed from the solidification of molten rock material (magma or lava).

Front

What are the two main types of igneous rocks?

Back

The two main types of igneous rocks are intrusive (plutonic) and extrusive (volcanic).

Front

What is the difference between intrusive and extrusive igneous rocks?

Back

Intrusive igneous rocks form from magma that cools slowly below the Earth's surface, while extrusive igneous rocks form from lava that cools quickly at the surface.

Front

What is granite?

Back

Granite is an intrusive igneous rock composed mainly of quartz, feldspar, and mica.

Front

What is basalt?

Back

Basalt is an extrusive igneous rock that is dark in color and primarily composed of pyroxene and plagioclase.

Front

What is obsidian?

Back

Obsidian is a naturally occurring volcanic glass formed from rapidly cooled lava.

Front

What is pumice?

Back

Pumice is a light, porous volcanic rock that forms when lava cools quickly and traps gas bubbles.

Front

How does cooling rate affect crystal size in igneous rocks?

Back

Slower cooling allows larger crystals to form, while faster cooling results in smaller crystals.

Front

What is the relationship between magma and lava?

Back

Magma is molten rock beneath the Earth's surface, while lava is magma that has reached the surface.

Front

What is the significance of crystal size in identifying igneous rocks?

Back

Crystal size can indicate the cooling history of the rock; larger crystals suggest slower cooling.