Features of Igneous, Sedimentary, and Metamorphic Rocks

Igneous Rocks:
- Formed by the solidification of molten rock material (magma or lava)
- Classified into two types: intrusive (formed inside the Earth's crust) and extrusive (formed on the Earth's surface)
- Examples include granite, basalt, and obsidian
- Typically have interlocking crystals due to slow cooling underground or glassy texture due to rapid cooling on the surface

Sedimentary Rocks:
- Formed by the accumulation and consolidation of sediments (rock fragments, minerals, and organic materials)
- Classified into three types: clastic (formed from weathered rock fragments), chemical (formed from dissolved minerals), and organic (formed from the remains of plants and animals)
- Examples include sandstone, limestone, and shale
- Often contain fossils and exhibit layers or bedding due to deposition over time

Metamorphic Rocks:
- Formed from the alteration of pre-existing rocks (igneous, sedimentary, or other metamorphic rocks) through heat and pressure
- Classified into two types: foliated (exhibiting layers or bands) and non-foliated (lacking obvious layering)
- Examples include marble, slate, and schist
- Can have distinct textures such as crystals, grains, or layers, depending on the degree of metamorphism
These three types of rocks provide valuable insights into Earth's geological history and processes. Students can study their characteristics to understand how different rock types are formed and transformed over time.