metamorphic

met-uh-MOR-fik /ˌmet.əˈmɔː.fɪk/
adjectiveC1GRETOEFLSAT
scientific

Denoting rock that has undergone transformation by heat, pressure, or subterranean natural agencies.

Metamorphic rock changes structure and mineral composition without melting completely into magma.

The story behind the word. Combining Ancient Greek 'meta' (expressing change) and 'morphe' (form or shape). Metamorphic rocks literally undergo a complete 'change of form' under deep subterranean temperatures and crushing pressures.

Word relationships

  • transformed: Transformed is a broad general term, whereas metamorphic specifically denotes crystalline and structural changes in rock under heat and pressure.
  • altered: Altered implies any small change, whereas metamorphic indicates deep structural recrystallization.
  • unaltered: Describes rock that retains its original primary texture and composition.

Commonly confused with

  • igneous: Igneous rock forms from liquid magma cooling, while metamorphic rock remains solid while being changed by heat and pressure.

Word family

  • metamorphosis (noun): A complete change of form or structure
  • metamorphose (verb): To undergo a structural transformation

Collocations

  • metamorphic rock
  • metamorphic process
  • metamorphic zone
  • metamorphic grade

Example sentences

  • "Marble is a metamorphic rock that originates from humble limestone altered by intense underground heat." Petrology lecture
  • "Deep mountain roots subject rock layers to the metamorphic conditions of extreme subterranean pressure." Mountain geography

Memory hook

META (change) + MORPH (shape) = changing shape under intense pressure. Changed form under pressure.

When not to use

Do not use for rock formed from molten magma (igneous) or simple particle settling (sedimentary).

Fun facts

  • Slate, widely used for roofing tiles and old classroom blackboards, is a metamorphic rock that began as humble mudstone.

Related words

igneous, sedimentary

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