Chapter 6, Section 1 Igneous Rocks Igneous RockA rock that forms from the cooling and hardening of molten rock

Magma Lava Molten rock found under the Earth’s Surface Molten Rock found on the Earth’s surface

Felsic magma Mafic magma Light in color, very thick; has a high silica content Dark in color and very thin; low silica content

Intrusive igneous rocks Rocks that form underground from magma Take a long time to cool because underground (holds the heat in)

Extrusive igneous rock Forms on the Earth’s surface from lava Cools and hardens very quickly b/c on the Earth’s surface

Crystal size Porphyry Intrusive igneous rocks tend to have LARGE crystals The longer it takes the rock to cool, the larger the crystals will be VERY large crystals

Granite family Felsic magmas Granite Rhyolite Pumice Obsidian

Gabbro family Mafic magmas Gabbro Basalt Scoria Diabase

Diorite familyIntermediate magma Diorite and andesite