Rocks - Grade 6

Igneous rock forms in regions where –

• rock is heated to melting point then cooled to a solid.
• metallic minerals are put under extreme pressure.
• a river deposits sand and mud over a long time.
• evidence of organisms is becoming fossilized.

What is the primary process that turns sediments into sedimentary rocks?

• Organisms walking on layers of sediment, pressing particles together tightly
• Minerals within sediment, absorbing water, and undergoing a chemical reaction
• Upper layers of sediment, pressing down on lower layers of deposited sediment
• Magma cooling under the surface of Earth, crystallizing to form rock

Scientists classify igneous, metamorphic, and sedimentary 
rocks based on their –

• shape.
• color.
• formation.
• usefulness.

What are the three types of rocks?

• Metamorphic, Sedimentary, Mineral
• Metamorphic, Sedimentary, Igneous
• Metamorphic, Igneous, Compaction
• Metamorphic, Igneous, Cementation

Geologists might recognize a metamorphic rock by distorted, wavy layers because they were caused by -

• compaction and cementation.

• melting and crystallizing.

• erosion and deposition.

• pressure and heat.

Rock formed above ground with lava

• Sedimentary Rock
• Extrusive Igneous Rock
• Intrusive Igneous Rock
• Metamorphic Rock

Rock formed by heat and pressure underground

• Sedimentary Rock
• Extrusive Igneous Rock
• Intrusive Igneous Rock
• Metamorphic Rock

Only rock that contains fossils

• Sedimentary Rock
• Extrusive Igneous Rock
• Intrusive Igneous Rock
• Metamorphic Rock

Rock with smooth, glassy surface

• Sedimentary Rock
• Extrusive Igneous Rock
• Intrusive Igneous Rock
• Metamorphic Rock

Rock formed below ground by magma

• Sedimentary Rock
• Extrusive Igneous Rock
• Intrusive Igneous Rock
• Metamorphic Rock