Metamorphic rocks are either easy to identify or very difficult. Some textures or appearances, like foliation, are unique to metamorphic rocks. Foliation comes from the Latin meaning leafy. The texture is platy because it contains minerals like mica. However some nonfoliated textures like granoblastic or minerals that are large grained are difficult to distinguish from chemical sedimentary or plutonic igneous rocks. These rocks do not have a squished look.

On the identification chart we separate the rocks by texture and refer to them as foliated or nonfoliated. Both groups are further subdivided by coarse and fine grained, depending on the size of the minerals. Mineral groups that are found within each rock can also help to identify the type of metamorphic rock.

Mica (bluish) is aligned in a foliated texture
in this mica schist (thin section)

Granoblastic texture of quartzite (thin section)