rock types

Granite

light rock that has crystals large enough to be seen with the naked eye

Diorite

Gabbro

porphyritic granite

porphyritic diorite

porphyritic gabbro

rhyolite

andesite

basalt

porphyritic rhyolite

porphyritic andesite

porphyritic basalt

obsidian

pumice

scoria

rhyolite tuff

andesite tuff

basalt tuff

dark rock with either hardened ash or soft ash

phaneritic

a term used to describe igneous rocks that have large crystals that are visible to the naked eye.

aphanitic

a term used in geology to describe the texture of igneous rocks that have such fine grains that their mineral crystals are not visible to the naked eye.

porphyritic

igneous rocks with large crystals set in a fine-grained matrix.

porphyritic-phaneritic plutonic

a texture of igneous rock that has both large crystals (phenocrysts) and smaller groundmass crystals.

porphyritic-phaneritic volcanic

pegmatitic

a coarse-grained igneous rock that contains large crystals of quartz, feldspar, and mica.

glassy

vesicular

trapped air bubbles rapid cooling

pyroclastic

high silica and explosive when formed (ashy)

volcanic breccia

large rock chunks

tuff

a light, porous rock formed by the consolidation of volcanic ash.