The study of metamorphic rocks is extremely fascinating for people of all ages. From professional geologists to children who monger rocks, it is always interesting to study and see how one type of rock can become another under the right circumstances. Phyllite is one such rock and truly a marvel of creation.
Phyllite is quite a beautiful rock with various shades of whites and grays for coloring. It may also be found in some shades of green and red. Many of these will be shiny or appear to shimmer on the surface. It is considered a foliated metamorphic rock that is composed primarily of quartz, sericite mica, and chlorite. On the metamorphic chart of grain size, it would fall between slate and schist. It is much like slate in that it tends to break into sheets or slivers where formation layers are present. The easiest way to tell it apart from slate is by how it reflects the light. Slate has a very dull surface where phyllite will shine much more readily. Phyllite is also more wavy than slate without foliation.
In order to form phyllite, shale must first be changed into slate. Shale, one might say, is the grandparent of phyllite. When shale comes in contact with heat and pressure or certain chemical fluids, it metamorphosizes into slate. Slate, considered the parent of phyllite, can then be changed into phyllite by additional heat being added. If continued metamorphism is allowed, the phyllite would eventually change into a rock known as schist.
Phyllite has become somewhat of a sought after building material in recent years. Because it is more robust than slate, it is easier to work with and far less likely to shatter or crack during transport and construction phases. It also has a naturally non-slip surface when mined correctly. The most popular uses of this stone are countertops, accent stones for building facades, flooring, and roofing. Depending on how it will be used, phyllite can be mined to several different textures and finishes including: brushing to soften the appearance and create a gentler surface, flaming to reduce roughness and increase the quality of the finish, natural split to create high levels of texture, and honed to remove all texture and create a smooth surface. These different mining techniques will also determine the coloring and how the veining is visible in a final product.
Whatever the end destination of this fabulous metamorphic rock, it is for sure to bring beauty, strength, and style to any home or project.