Quartzite is the stone people are usually reaching for when they say they want marble. It is metamorphosed sandstone: quartz grains fused under heat and pressure until the rock is essentially solid quartz. Soft-looking veining, genuinely hard surface.
The facts
| Type | Metamorphic rock from sandstone. Siliceous stone, overwhelmingly quartz. |
|---|---|
| Acid resistance | As a siliceous stone it is “generally resistant to most acids” per the Natural Stone Institute. The practical reason it survives a kitchen where marble struggles. |
| Hardness | Around 7 on the Mohs scale. Harder than glass, harder than a steel blade, at the top end of what you will find in a natural slab. |
| Porosity | Low, but real. It still wants an impregnating sealer. |
| Heat | Excellent. Formed under extreme heat; handles hot cookware. |
| Fabrication | Hard on tooling. Quartzite eats blades that granite would barely notice. |
The mislabeling problem, and how we handle it
This is worth saying plainly, because it costs people money. A meaningful amount of stone sold as “quartzite” in the US is actually dolomitic marble or a soft quartzite with heavy calcite content. It looks identical on a showroom rack. It behaves like marble in your kitchen. It etches.
The trade tests for it two ways: a glass scratch test (real quartzite scratches glass; marble doesn’t), and a discreet acid test on an offcut (marble fizzes and dulls; quartzite doesn’t react). We test before we fabricate, on an offcut, and we tell you what we find even when the answer is inconvenient. If your “quartzite” turns out to be dolomitic marble, you deserve to know that before it is installed, not after the first lemon.
Where it shines
- Kitchens where you want marble looks and granite performance
- Bar tops and islands that take real abuse
- Book-matched feature walls and waterfall edges
- Anyone who has been talked out of marble and is not happy about it
Think twice about
- Budget-driven projects. It is usually the pricier natural stone
- Buying unverified “quartzite” from a rack without a test
- Complex shapes on a tight timeline; it is slow to cut
Care and sealing
The first coat is on us
Every natural stone top we deliver leaves our shop with its first coat of impregnating sealer already applied and cured, included, not an upsell. You start protected from day one. After that, resealing is a ten-minute job you can do yourself; we’ll show you how on install day and tell you honestly how often your slab actually needs it, because it varies enormously between stones.
What sealing does, and what it doesn’t
There is a lot of confused advice about this, so here is the honest version, which matches the Natural Stone Institute’s own guidance.
Impregnating sealers “do not actually seal the stone, but more correctly act as a repellent rather than a sealer.” They soak into the stone’s pores and buy you time. A spill beads up and sits there instead of soaking straight in. The Institute is blunt about the limit: “sealing does not make the stone stain proof, rather it makes the stone more stain resistant.”
So a sealed counter is not a license to leave red wine overnight. It’s the difference between wiping up a spill and living with it.
The simple test for when to reseal
Put a few drops of water on the stone and leave it for fifteen minutes. Wipe it off. If the stone underneath has darkened, the sealer has worn thin and it’s time for another coat. If it looks the same you are fine, so leave it alone. Do this in the busiest spot, which is usually next to the sink or the cooktop.
Cleaners to keep away from it
- Anything acidic. The Natural Stone Institute warns that “products containing lemon, vinegar or other acids may dull or etch calcareous stones.”
- Scouring powders and creams. They “often contain abrasives that may scratch certain stones.”
- Rust removers and some toilet-bowl cleaners. Many contain trace hydrofluoric acid, which “attacks silicates in addition to other minerals”. That means it damages granite and quartzite too, not just marble.
- Never mix ammonia and bleach. The Institute’s warning is worth repeating exactly: “This combination creates a toxic and lethal gas.”
The two habits that matter most
Blot, don’t wipe. When something spills, the Institute’s advice is to “blot the spill with a paper towel immediately. Don’t wipe the area, it will spread the spill.”
Coasters and trivets. Under glasses, and under anything that came off a burner. It costs nothing and it prevents most of the damage we get called out to look at.
How we fabricate it
Quartzite’s hardness is exactly where a robotic waterjet earns its keep. Abrasive waterjet cutting doesn’t care how hard the stone is. It erodes rather than grinds, so we get clean radii and chip-free edges on a material that punishes conventional tooling. Every quartzite top is tested, cut, polished, inspected and sealed in our Everett shop.
Finishes and slab sizes
There is no standard size in natural stone
This is the part that surprises people most. Engineered materials come off a press at a fixed size, every time. Natural stone does not. A slab starts as a block cut out of a quarry face, and the block is whatever the geology allowed the quarry to extract that day, so length, width and even thickness vary from block to block, and often between slabs cut from the same block.
Two slabs of the same named stone, bought six months apart, can differ by a foot (about 30 cm) in length. It is not a defect; it is what quarried material is.
As a rough guide, most of the natural stone slabs we handle fall somewhere between roughly 105″ and 130″ long (about 265–330 cm) and 65″ to 78″ high (about 165–200 cm). Treat that as a range we see rather than a specification. The only dimensions that count are the ones on the slab you pick.
What that means for your project
- Buy the whole job at once. Slabs from one block match. Slabs from the next block will not, in size or in veining.
- Seam placement is decided by the slab, not the drawing. We lay your job out on the actual slab dimensions, which is why we template before ordering rather than after.
- Yield varies. A heavily veined or fissured slab has less usable area, so two projects of identical square footage can need a different number of slabs.
- Buy a little extra. If a piece is damaged years later, matching it from stock is usually impossible. An offcut kept in a garage has saved more than one of our clients a full re-do.
Finishes
| Polished | High-gloss. Deepens color and makes veining read strongest. The standard finish on most granite. |
|---|---|
| Honed | Matte, low-gloss. Softer looking, and on marble it hides etching far better than polish does. |
| Leathered / brushed | A textured satin finish that keeps color depth while hiding fingerprints and water spots. Popular on dark granite. |
Not every finish is available on every stone. It depends on the material’s hardness and structure. We will tell you what a given slab will take.
Where these facts come from
- Natural Stone Institute, Care & Cleaning of Natural Stone