Phyllite is a low-grade pelitic metamorphic rock. It is distinguished from lower grade slate by having a higher proportion of newly crystallised minerals, and accordingly, a higher sheen. It is is distinguished from higher grade schist in that the metamorphic minerals are still too small to be seen with the naked eye. Note that the layering present here is not sedimentary in origin, but tectonic. Growth of new phyllosilicates such as muscovite and chlorite creating a planar structure in the rock.