Answer:
It is formed by intensive pressure.
Step-by-step explanation:
Foliated metamorphic rocks are formed by heat and direct pressure being applied to the rock. The stripes that appear will indicate the direction of the most and consistent intense pressure. The grains will change their position and realign themselves perpendicular to this. Examples include slate and gneiss. Different sized grains might move to different levels leaving behind bands that are different in appearance and structure.