What are the characteristics of foliated and non-foliated metamorphic rocks?
Foliation is the repetitive layering of rocks due to intense directed pressure. Foliated rocks are characterized by linear streaks that vary in width. Non-foliated metamorphic rocks do not have these streaks.
It occurs among metamorphic rocks that are subjected to intense directed pressure which causes the minerals within the rock to flatten or realign perpendicularly from the area of greatest pressure.