Phyllite and natural slate are both metamorphic rocks. They have formed over millions of years through intense heat and pressure inside the Earth’s crust. Although both formed in a very similar way, phyllite has been subjected to far higher temperatures and greater pressures than natural slate. This increased pressure causes the clay inside the phyllite to break down and form mica – the crystals that can be found in all metamorphic rock.
Mica crystals in phyllite and natural slate
Micas are a group of silicate minerals. Common in metamorphic and igneous rock, mica crystals create a unique aesthetic appearance to a material’s exterior which varies depending on the grade of the mica flakes.
Phyllite has fine-grained mica flakes. Natural slate has extremely fine-grained mica flakes. Because the mica flakes in phyllite are larger than in natural slate, they are more visible on the material’s surface. This gives phyllite its satin-like sheen and attractive visual aesthetic.
Phyllite vs natural slate: aesthetics and performance
In terms of durability and weather resistance, both phyllite and natural slate are excellent roofing materials. The differences in physical attributes and capacity as a construction material are small, with both materials providing excellent performance levels. Phyllite is harder, denser, and stronger than natural slate but only by a small margin.
When it comes to aesthetics, however, phyllite and natural slate are noticeably different. Phyllite is generally much brighter than natural slate. It has an exterior sheen which reflects the light and differs depending on the direction of the rock’s grain and length of the slate. This means that at different times of the day, depending on the angle of light, phyllite may take on a completely different appearance. This creates the unique aesthetic appearance, loved by architects and roofing specialists alike.
Different types of natural slate do have variations in colour and brightness. For example, our Del Carmen slates have an attractive blue-black colour while our Domiz natural slate has a rich blue grey colour similar to traditional Welsh slates. Phyllite, however, is distinctly different in appearance than natural slate and is often selected for its unique look.
Premium quality roofing materials from SSQ
As you can see, both Phyllite and natural slate are excellent materials for roofing, cladding, and flooring. At SSQ, we mine, produce, and supply a wide variety of roofing products using both natural slate and Phyllite. All our slates are of the highest possible quality and can be used to meet a variety of project specifications.
If you’d like to find out more about using Phyllite or any of our natural slates for your next roofing project, get in touch today. You can call us on 020 8038 6454 or contact us online for more information.