Science - Ch. 4 Lesson 2 Rocks & Rock Cycle

Intrusive Igneous Rocks

rocks with large crystals such as granite that form due to slow cooling deep beneath Earth's surface

Used to classify Igneous Rocks

texture, sediment between grains

Pumice

gas - rich lava erupts from a volcano and it can form a rock with numerous holes

Rock's Composition

geologists can use color to determine a rock when minerals are hard to identify

Texture of an Extrusive Rock

layered, fine-grained

Type of Igneous Rock that forms depends on

magma composition, where the lava or magma cools and crystallizes, the cooling rate (fast or slow)

Extrusive Igneous Rocks

rapid cooling gives these rocks a fine-grained texture (small crystals)

Obsidian

rock with a glassy texture that forms when lava cools quickly on Earth's surface