igneous
IG-nee-us
/ˈɪɡ.ni.əs/
Relating to or denoting rock formed through the cooling and solidification of magma or lava.
Covers both intrusive rock (cooling underground slowly) and extrusive rock (cooling above ground quickly).
The story behind the word. From Latin 'igneus' (fiery), derived from 'ignis' (fire—the root of 'ignite'). Early geologists called these rocks 'fiery' because they originate from intense heat and molten rock.
Word relationships
- volcanic: Volcanic specifically refers to igneous rocks erupted on the surface, whereas igneous includes subterranean cooled magma.
- sedimentary: Formed from accumulated particle debris rather than solidified molten rock.
Commonly confused with
- metamorphic: Igneous forms directly from liquid melt cooling, whereas metamorphic alters existing solid rock without full melting.
Word family
- ignite (verb): To set on fire or catch fire
- ignition (noun): The action of setting something on fire
Collocations
- igneous rock
- igneous intrusion
- igneous formation
- igneous activity
Example sentences
- "Basalt and granite are two widespread types of igneous rock produced by cooling subterranean melt." Geology overview
- "The island's black sand beaches originated from eroded igneous rock formed during past volcanic eruptions." Volcanic geology
Memory hook
IGNEOUS = IGNITE = born from subterranean fire. Born from fiery molten rock.
When not to use
Do not use for sedimentary or metamorphic rocks.
Fun facts
- Pumice is an igneous rock so filled with trapped gas bubbles that it can actually float on water.
Related words
Explore more words
eruption, geothermal, earthquake, Ionic, permafrost, stratification
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