Classification and Characteristics of Igneous Rocks

The video tutorial explains igneous rocks, focusing on their formation and classification. It describes how igneous rocks form from the cooling and solidification of magma or lava, distinguishing between intrusive and extrusive types. Intrusive rocks form inside the Earth, cooling slowly to create large crystals, while extrusive rocks form on the surface, cooling quickly with small or no crystals. The video also highlights the differences between magma and lava and provides examples of igneous rocks like granite, basalt, and obsidian.

What is the primary basis for classifying rocks?

• Density

• Method of formation

• Texture

• Color

What are the three main categories of rocks?

• Igneous, Sedimentary, Metamorphic

• Igneous, Volcanic, Sedimentary

• Sedimentary, Metamorphic, Volcanic

• Volcanic, Plutonic, Metamorphic

How do igneous rocks form?

• From the accumulation of organic material

• From the transformation of existing rocks

• From the compression of sediments

• From the cooling and solidification of magma or lava

What is the difference between magma and lava?

• Magma is molten rock underground, lava is on the surface

• Magma is molten rock on the surface, lava is underground

• Magma is cooler than lava

• Magma is solid rock, lava is liquid rock

What characterizes intrusive igneous rocks?

• They have small crystals

• They form on the Earth's surface

• They have large crystals

• They are vesicular

Which rock is an example of an intrusive igneous rock?

• Pumice

• Obsidian

• Granite

• Basalt

What is a key feature of extrusive igneous rocks?

• They form deep underground

• They form slowly

• They have large crystals

• They may have air bubbles

Which rock is an example of an extrusive igneous rock?

• Pegmatite

• Granite

• Gneiss

• Obsidian

What is the texture called when air bubbles are trapped in extrusive rocks?

• Crystalline

• Porous

• Vesicular

• Granular

What are igneous rocks with small or no crystals called?

• Metamorphic

• Extrusive

• Plutonic

• Intrusive