Summary:
- Igneous rocks are classified by composition and texture.
- Categories go from from felsic to ultramafic.
- Texture indicates how a rock cooled.
- Magma that cools rapidly has small or no visible crystals, while magma that cooled slowly has large crystals.
- Use the resource below to answer the questions that follow.
- The questions are: Is this an intrusive or an extrusive igneous rock?
- How does the rate of magma cooling affect crystal size?
- What is the name of the texture if extremely small crystals form?
- Where do rocks like this form?