Gneissic Layering
Gneissic Layering is a type of foliation in which the planer orientation is produced by alternating layers of different mineral composition. Rocks with gneissic layering are charcateristically course grained and represent a higher grade of metamorphism in which the minerals are recrystallized, stretched, crushed and rearranged completely. The specimen pictured here is Gneiss, #17 in your rock box. Notice the light and dark banding in one general direction from left to right.