Stone is a commonly used material in construction and architecture. Depending on its look and where it’s placed, it can dramatically alter the look of areas such as a garden, patio, driveway, or rooftop. So it goes without saying that people take a lot of time and care to choose the right one that perfectly fits their vision.
Now two of the most popular stone types around are slate and bluestone. These visually look very similar, often confusing people about their differences. Some even say they are two names for the same thing.
But this is not the case. While they are technically both types of flagstone, there are a few key differences in their characteristics and color that differentiate them from each other.
The main difference between slate and bluestone is that bluestone has a unique looking blue/gray color scheme to it. Because of the way blue stone is formed, it’s also very durable, giving it fantastic longevity.
Slate, however, can come in a wide array of colors ranging from browns to reds to blacks, with little bits of blue and green worked in. Slate is quite a bit smoother than bluestone and, while is it quite a hard material, it’s also very brittle and prone to cracking, so it’s generally sealed like other floor types to give it an extra degree of strength.
What is slate?
Slate is one of the most versatile rock types around. Because of its varying colors and readily available, you’ll see it used almost anywhere.
A common application is roofing due to how thin it can be cut, making it very light, and its smooth surface allows it to shed water exceptionally easily. But it’s still great for floors and garden paving.
It’s comprised of hardened clay or sedimentary rock compacted over time, and the water content becomes squeezed to create shale. This shale is then further compacted and baked at a very high temperate to turn it into slate, which can then be split into thinner sheets.
We most commonly associate slate with having a grey color, but depending on where the slate comes from, it can take on several different colors – so be sure to shop around and find the one that suits you best!
What is bluestone?
Like slate, bluestone tile is a flagstone form formed by river sedimentary rock fusing over time. But it’s differentiated from slate due to its blue or blue/gray color.
It also has different properties than slate in terms of its strength. It’s a durable and weather-resistant material and is naturally a little more textured than slate, making it a better choice for paths as it has a bit of extra grip.
Generally speaking, a bluestone tile is considered a little more ‘upscale’ and often used on more premium constructions due to its higher price.
What are the differences between slate and bluestone?
So while we’ve established that they are similar in how they are made, is there much different about them beyond just color?
Absolutely, and you must consider these when planning out your construction so you can be sure you’re picking the most appropriate one for your needs.
As the name suggests, bluestone often has a patchy quality that mixes various shades of blues and greys that come together to make an appealing look for something like a driveway. Depending on your preference, you can find stone tiles that lean more towards a deep blue or more of an ashy grey.
Slate, however, is much more diverse in its color palette, where it’s not unusual to find slate tiles with heavy brown, red, or yellow undertones. This can often make it easier to work with your chosen decor style. But ultimately, the choice is yours.
Bluestone is quite a bit more expensive than slate. That is not to say it’s ‘better’ per se, but the higher price tag usually means it’s more commonly seen on construction projects with bigger budgets. Thus an association between bluestone and a premium product has been established.
That said, there are plenty of ways to work bluestone into a budget project, and we encourage you to contact your local supplier to get up-to-date prices before writing bluestone off.
Slate, on the other hand, is a little bit more budget-friendly due to how easy it is to quarry and how widely available it is. Providing there is a color scheme you like, it’s going to be much easier to source and work into your construction plan compared to bluestone.
Both of these flagstone types are hard. You’re not going to find them turning into powder after a little bit of rainfall by any means.
However, the critical distinction between the two is that slate is more brittle than bluestone, meaning it is more liable to crack when subjected to heavy forces.
You can take some steps to reinforce the slate and make it more capable of dealing with high-traffic areas such as pathways or driveways. But in general, bluestone will hold its own here better.
Because of how well slate can be split into tiles after quarrying, it can be cut into much thinner and lighter slabs. This makes it perfect for applications where the flagstone needs to be lightweight, such as a roof where you don’t want too much weight to be put on the joists.
Bluestone is quite a bit heavier and resilient, making it great for driveway tiles as it’s not going to move around easily.
5. Surface texture
Slate often has a very smooth surface texture which is one of the reasons for its widespread use for roof tiles, as water sheers off it.
But this smooth quality makes it less appropriate for something like a footpath when you need a bit of grip so as not to slip and fall over.
This is where bluestone can often be better after it’s split into slabs. It has a natural texture to it, serving as a kind of grip that people love for things like driveways or gardens. It’s far safer to be on bluestone pavers in the rain.
6. Needs to be sealed
Because slate is a porous rock and is very prone to absorbing water, it must be sealed before use. Depending on your seal, you may need to apply multiple coats of this before it adequately repels water.
Now while it is also recommended to seal in bluestone for longevity’s sake, it’s more just to protect it from discoloration and dirt than to remove its water absorption properties like slate.
Slate vs Bluestone: Are they the same?
Both of these stone types share many similar properties, and in many cases, they can be interchangeable as they are both appropriate for so many different use case scenarios.
But there are a few differences in their looks and qualities that may make you lean towards one more than the other.
- Bluestone has a distinct blue/grey color than can appear patchy and vary in strength depending on where it’s sourced from. Slate, however, can come in various colors, including grey with red, yellow, or brown overtones.
- Because of the slate’s wider availability and ease of quarrying, it’s relatively cheaper than bluestone. Because bluestone is a little more expensive, it has a deeper association with premium quality and looks.
- While both rock types are pretty hard, slate is the more brittle. They often require sealing to let them withstand the rigors of day-to-day use. Bluestone, on the other hand, is quite tough by itself.
- Because of slate composition, it can be cut into much thinner and lighter slabs. In contrast, bluestone slabs are often much heavier, making them less appropriate for roofing and better for things like a driveway that will need to bear more weight.
- Once sealed, slate has a smooth and slippy texture that repels water wonderfully but is much more difficult to walk on. Whereas bluestone pavers have a nice natural texture that provides an intrinsic grip you can safely walk on.
Both tile types need to be sealed, but slate needs filling much more than bluestone; otherwise, it will absorb too much water and weaken.