Igneous Rocks Vocabulary

aphanitic
Igneous rock texture with small crystals or grains not visible with the naked eye.
basalt
Fine-grained mafic igneous rock.
batholith
Large mass of igneous rock formed at depth then exposed through erosion.
caldera
Very large depression formed by the collapse of a composite volcano.
cinder cone
Small volcano made primarily of pyroclastics.
dike
Intrusive igneous rock feature that cuts through surrounding rock.
diorite
Intermediate coarse-grained igneous rock.
extrusive
Igneous activity at the Earth's surface.
felsic
Igneous rocks with a light-colored granitic composition of feldspar and quartz.
gabbro
Dark green to black coarse-textured intrusive igneous rock.
granite
Light colored coarse-textured intrusive igneous rock.
igneous
An igneous rock forming from the cooling and crystallization of liquid rock.
intrusive
Igneous activity beneath the Earth's surface.
laccolith
Large mass of igneous intruded between existing rock layers.
lava
Molten rock on the Earth's surface.
mafic
Igneous rocks with dark-colored mineral composition of magnesium and iron materials.
magma
Molten rock and gasses beneath the Earth's surface.
mineral
A naturally occurring, inorganic solid with crystalline form, and specific chemical composition.
obsidian
Volcanic glass with no crystals due to its rapid cooling.
phaneritic
Igneous rock texture with visible crystals of mostly equal size.
pluton
Structure formed by cooling magma beneath the surface.
porphyritic
Igneous rock with large crystals surrounded with a fine grained or glassy matrix.
pumice
Glassy volcanic rock with many gas voids or bubbles.
pyroclastic
Relating to igneous material ejected from volcanoes.
rhyolite
Light colored fine-textured extrusive igneous rock.
rock
A rock is an aggregate of one or more minerals.
shield
Broad gentle sloping volcano made with fluid basalts.
sill
Intrusive igneous rock body that intrudes parallel to existing rock layers.
stratovolcano (composite)
Volcano composed of lava and pyroclastic layers.
vent
Pipe-like conduit that conducts lava to the volcanic crater.