Slate and granite are two distinct types of natural stone that can be used to achieve very similar effects, particularly when darker varieties are used. Although their mineral composition can differ drastically, both are extremely hardy, possessing very similar densities, and will last a lifetime provided the stone is of a high quality. Here we’ll take a look at the two in greater detail to help you decide which one is right for your Newport Beach, CA project.
The color of slate varies from different shades of grey to bluish greens. It is an extremely fine-grained stone that forms when layers of clay or volcanic ash are compressed over time under great weight. These layers are clearly visible when looking at a cross section of slate and it is this layering that gives slate it’s unique, randomly textured look when stacked in sheets.
Slate absorbs very little water from the surrounding environment, meaning it is highly resistant to water damage, cracking and freeze thaw damage. In fact, slate is practically waterproof, which is why it has been widely used as a roofing material for hundreds of years. This is also what makes it excellent for swimming pool patios and other areas that will receive a high amount of moisture. While slate is easy to clean and won’t stain, it can be susceptible to scratching.
Most slate found in California and the rest of the US is either quarried in eastern states such as Vermont, Pennsylvania and New York, or imported from Brazil and occasionally from China.
By contrast, granite has a much coarser grain with a wider range of colors in general and within the grain of individual slabs. Granite often has a mottled appearance because of the variety of its composition and comes in colors as diverse as pink, green, blue and black, depending on its makeup.
Granite is more porous than slate, but not enough to make it any less tough, although it can be more susceptible to staining if untreated. Granite consists of a high percentage of quartz and feldspar, but it isn’t just the composition that makes granite different from slate: they’re also formed by very different processes. Granite is formed when magma cools beneath the surface of the earth, forming crystals and fusing with surrounding rock. This makes granite an incredibly strong rock without the lateral foliation of slate.
Which one for my project?
Slate is definitely a great way to go if you’re look for a cool-colored uniform surface. Dark slate absorbs a lot of heat in the sun, so while it may become a little uncomfortable in direct sunlight, it works well to provide warmth in shaded areas or soak up the morning sun and provide warmth throughout the afternoon and evening. Paler shades, of course, are less susceptible to heat.
If a more varied, motley surface is your thing, granite is definitely the preferred choice. The sparkle of a granite surface and the visual depth of polished granite make it an attractive option for many homeowners. The reflectivity of granite also makes it slightly less susceptible to heat.
Ultimately the choice between the two comes down to aesthetic, slate being more subtle and gentle on the eye, while granite is characterful and varied.