Precedes low grade and high grade metamorphism. Planes cut original bedding of a sedimentary rock at an angle. Preferred orientation - mineral grains in a metamorphic rock that are all aligned in the same direction, i.e. micas aligned parallel to the foliation. Often oriented at an angle to the original bedding of a sedimentary rock. Produced by metamorphism of shales and more rarely volcanic tuffs.
Foliation has a coarse, wavy appearance.
Doesn't split along foliation. Has undergone little or no deformation. Platy crystals randomly oriented. Produced during medium to high grade metamorphism of mafic rocks.