Definition

1. Noun:
   • A type of metamorphic rock: "schist" refers to a medium- to coarse-grained metamorphic rock characterized by a well-developed, foliated structure. This foliation, called schistosity, allows the rock to be easily split into thin layers or flakes. Schist typically forms under conditions of high temperature and pressure, which cause the mineral grains within the original rock to recrystallize and align into parallel layers.

Usage Examples

• Noun:
  • The mountains in that region are composed primarily of mica schist.
  • Geologists identified the sample as a garnet schist due to its distinctive red crystals.
  • The schist split cleanly along its foliation plane when struck with a hammer.

Advanced Usage

• In geological classification: The specific type of schist is often named after its most prominent mineral constituent (e.g., , , , ). This naming convention provides immediate information about the rock's composition.
  • The amphibolite facies is known for producing common schists like biotite schist.

Variants and Related Words

• Schistose (adj): Having the characteristic foliated, layered texture of schist.
  • The rock exhibited a strongly schistose texture.
• Schistosity (n): The property or process of splitting into thin layers, which is the defining structural feature of schist.
  • The intense pressure resulted in the pronounced schistosity of the rock.

Synonyms

• Foliated metamorphic rock: A broader category that includes schist, gneiss, and slate, all sharing a layered or banded structure.
• Layered rock: A general, non-technical term describing rocks with a visibly layered appearance.

Related Phrases and Terms

• Blueschist: A specific variety of schist that forms under high pressure and relatively low temperature, containing minerals like glaucophane that give it a blue color.
• Greenschist: A schist dominated by green minerals like chlorite, epidote, or actinolite, typically formed at lower grades of metamorphism.

Noun

1. any metamorphic rock that can be split into thin layers