Magma, igneous rocks, and intrusive activity

A volcanic rock that is extremely vesicular and glassy.

The extrusive equivalent of diorite.

The extrusive equivalent of gabbro.

The extrusive equivalent of granite.

An open cavity in a volcanic rock that was filled by a gas bubble when the lava was still mainly liquid.

The sizes, shapes, and arrangements of mineral grains in an igneous rock.

Igneous rock with the highest silica content.

Igneous rock with the lowest silica content.

High silica content

low silica content

• Fine grained texture
• crystals can't be seen with the naked eye

• Coarse-grained
• minerals can be seen with the naked eye.

 Large phenocrysts embedded in ground mass

Voids left by gas bubbles.

Molten rock ejected into the atmosphere that cools quickly and becomes solid without forming grains.

• Consolidation of individual rock fragments ejected during explosive volcanic eruptions.
•  tuff or welded tuff

Exceptionally coarse grained igneous rock, which most of the crystals are more that 1 centimeter in diameter.

• Granite(intrusive)/ rhyolite (extrusive)
• obsidian (extrusive)
• Pumice

Andesite(extrusive)/diorite(intrusive)

Basalt(extrusive)/gabbro(intrusive)

• tuff/welded tuff: small ash and glass particles
• breccia: composed mainly of particles larger than ash