Metamorphic rocks are created from other rocks that have experienced extreme heat and pressure, and like igneous and sedimentary rocks, metamorphic rocks also have characteristics that are called properties. The first property is called foliated and banded. This means that a metamorphic rock has ribbon-like stripes. This is caused by mineral crystals lining up together during metamorphosis. The second property is foliated and slaty. This means a rock breaks in thin layers or sheets. The third property, non-foliated, means that the rock has no layers or stripes. The crystals are fused together. The final property of metamorphic rocks is called friable. If a metamorphic rock is friable, it is brittle. When it breaks it produces fibers or layered particles.
This is gneiss, a foliated and banded metamorphic rock.
This is slate, a foliated and slaty metamorphic rock.
This is quartzite, a non-foliated metamorphic rock.
This rock formation is a good example of the friable property.