Igneous Rock Identification and Composition

This video from Moomoomath introduces igneous rocks, explaining their formation from magma. It distinguishes between extrusive and intrusive rocks, highlighting their crystal sizes. The video details five types of igneous rocks: obsidian, granite, basalt, scoria, and rhyolite, describing their composition, texture, and hardness. It concludes with a prompt to explore more resources on igneous rocks.

What are the two main types of igneous rocks based on their formation?

• Sedimentary and Metamorphic

• Extrusive and Intrusive

• Plutonic and Metamorphic

• Volcanic and Sedimentary

Which type of igneous rock is formed when magma cools quickly on the Earth's surface?

• Sedimentary

• Intrusive

• Metamorphic

• Extrusive

What is the primary composition of obsidian?

• Augite and Hornblende

• Feldspar, Quartz, and Mica

• Plagioclase and Pyroxene

• Quartz, Alkali, and Feldspar

Which igneous rock is known for having medium to coarse grain crystals?

• Basalt

• Granite

• Obsidian

• Rhyolite

What minerals make up granite?

• Augite and Hornblende

• Plagioclase and Pyroxene

• Feldspar, Quartz, and Mica

• Quartz, Alkali, and Feldspar

Which rock is dark, dense, and very fine-grained?

• Basalt

• Granite

• Obsidian

• Rhyolite

What is scoria primarily composed of?

• Quartz, Alkali, and Feldspar

• Feldspar, Augite, and Hornblende

• Plagioclase and Pyroxene

• Feldspar, Quartz, and Mica

Which igneous rock can float in water due to its porous texture?

• Granite

• Basalt

• Obsidian

• Rhyolite

What is the texture of rhyolite?

• Glassy

• Coarse-grained

• Medium-grained

• Very fine and often porous

Which of the following rocks is not an extrusive igneous rock?

• Rhyolite

• Basalt

• Obsidian

• Granite