What is the difference between foliated and nonfoliated

Answer: Foliated metamorphic rocks such as gneiss, phyllite, schist, and slate have a layered or banded appearance that is produced by exposure to heat and directed pressure. Non-foliated metamorphic rocks such as hornfels, marble, quartzite, and novaculite do not have a layered or banded appearance.

foliated has a layered/banded appearance that is produced by exposure to heat. non foliated do not