Which of the following is NOT a metamorphic rock?

The correct answer is Sandstone.

• Sandstone is NOT a metamorphic rock.

Key Points

• Metamorphic rocks are rocks that have become changed by intense heat or pressure while forming.
  • In the very hot and pressured conditions deep inside the Earth's crust, both sedimentary and igneous rocks can be changed into metamorphic rock.
  • ​Metamorphic rock can be formed locally when rock is heated by the intrusion of hot molten rock called magma from the Earth's interior.
    • Some examples of metamorphic rocks are gneiss, slate, marble, schist, and quartzite.
  • Marble, Slate, and quartz are formed after metamorphism. They changed in their original form due to extreme temperatures and pressure.
  • The three types of metamorphism are Contact, Regional, and Dynamic metamorphism.
  • Contact Metamorphism occurs when magma comes in contact with an already existing body of rock.

Additional Information

• Sandstone :
  • Sandstone is a sedimentary rock composed of sand-size grains of mineral, rock, or organic material.
    • It also contains a cementing material that binds the sand grains together and may contain a matrix of silt- or clay-size particles that occupy the spaces between the sand grains.
  • Sandstone is a sedimentary rock composed mostly of quartz sand, but it can also contain significant amounts of feldspar, and sometimes silt and clay.
  • Sandstone that contains more than 90% quartz is called quartzose sandstone.