U3S2 Igneous Rocks

Vocabulary flashcards covering key igneous rock concepts: formation, types, texture, minerals, and common rocks.

Igneous rock

Rocks formed when molten material (magma or lava) cools and solidifies.

Magma

Molten rock located beneath Earth's surface that cools slowly to form intrusive igneous rocks.

Lava

Molten rock that erupts onto the surface and cools rapidly to form extrusive igneous rocks.

Intrusive igneous rock

Rock that forms when magma cools and solidifies below Earth's surface; typically large crystals and a coarse texture.

Extrusive igneous rock

Rock that forms when lava erupts and cools rapidly on Earth's surface; typically small crystals and a fine texture.

Texture

The feel or appearance of a rock's surface, related to crystal size.

Coarse texture

Texture with large crystals formed by slow cooling underground.

Fine texture

Texture with small crystals formed by rapid cooling on the surface.

Quartz

A common mineral in igneous rocks (silicon dioxide, hard and glassy).

Feldspar

A group of common rock-forming minerals in igneous rocks.

Mica

A mineral in igneous rocks that forms flat, sheet-like crystals.

Amphibole

A mineral group found in igneous rocks.

Granite

A coarse-grained intrusive igneous rock, mainly quartz, feldspar, and mica; used for countertops.

Basalt

A fine-grained extrusive igneous rock; common in construction as crushed rock.

Pumice

A light, porous extrusive rock used as a cleaning material.

Origin (of igneous rocks)

Classification by where cooling occurs: magma (below surface) or lava (on surface).

Composition

The minerals that make up a rock (e.g., quartz, feldspar, mica; metals).

Molten

Rock that has melted; liquefied by extreme heat.