Igneous rocks

What are igneous rocks primarily formed from?

• Metamorphism of existing rocks
• Chemical reactions in water
• Compression of sediments
• Cooling and solidification of magma or lava

Which of the following is an example of an igneous rock?

• Granite
• Sandstone
• Limestone
• Slate

What is the difference between intrusive and extrusive igneous rocks?

• Intrusive rocks are formed from sediment; extrusive rocks from magma
• Intrusive rocks contain more gas bubbles than extrusive rocks
• Intrusive rocks are always lighter in colour; extrusive rocks are darker
• Intrusive rocks cool slowly underground; extrusive rocks cool quickly on the surface

Which process leads to the formation of volcanic rocks?

• Eruption of magma onto the Earth's surface
• Weathering of surface rocks
• Burial of sediments under pressure
• Transformation of minerals under heat and pressure

What type of igneous rock is formed from lava that cools quickly?

• Diorite
• Gabbro
• Pumice
• Basalt

Which of the following characteristics is common in igneous rocks?

• Crystalline structure
• Layered appearance
• Fossils present
• Soft and easily eroded

What is the primary mineral found in granite?

• Quartz
• Calcite
• Mica
• Feldspar

How are igneous rocks classified?

• By their origin and texture
• By their colour and size
• By their weight and shape
• By their age and location

What role does temperature play in the formation of igneous rocks?

• Extreme cold forms metamorphic rocks
• Moderate temperatures create sedimentary layers
• Low temperatures lead to crystallisation of gases
• High temperatures cause melting of rock

Which igneous rock is known for its light colour and coarse texture?

• Scoria
• Basalt
• Obsidian
• Granite