Igneous Rocks Quiz

What is the thickness range of the Earth's crust?

What is the usual appearance of rocks with mineral grains that only touch at points?

• Shiny

• Glossy

• Dull

• Transparent

What type of rocks are often gritty to touch?

• Crystalline rocks

• Non-crystalline rocks

• Metamorphic rocks

• Igneous rocks

Non-crystalline rocks are often described as:

• Glossy

• Shiny

• Dull

• Transparent

What type of rock is formed from the cooling and solidification of magma or lava?

• Sedimentary

• Metamorphic

• Igneous

• Fossiliferous

Which type of rock is formed from the alteration of existing rock by heat, pressure, and/or chemically active fluids?

• Igneous

• Sedimentary

• Metamorphic

• Fossiliferous

Why are igneous rocks hard?

• Because they are made of soft minerals

• Because the minerals they contain are hard

• Because they are formed under high pressure

• Because they contain a lot of water

What makes the mineral crystals in igneous rocks strong?

• Their size

• Their composition

• Their interlocking nature

• Their color

What is the characteristic pattern of crystals in igneous rocks?

• Layered

• Interlocking

• Fragmented

• Rounded

Extrusive igneous rocks are formed from:

• Magma that cools slowly beneath the Earth's surface

• Lava that cools quickly on the Earth's surface

• Sediments that are compacted and cemented together

• Rocks that are changed by heat and pressure