Engineered quartz is not a stone you dig out of the ground. It is roughly 90 to 93 percent crushed natural quartz bound with about 7 to 10 percent polymer resin, pressed and cured into a slab. That resin is the whole story of this material — it is why quartz never needs sealing, and it is why you cannot put a hot pan on it.
The facts
| Type | Engineered composite. Crushed quartz aggregate in a polyester resin binder, with pigments for color and pattern. |
|---|---|
| Composition | Roughly 90–93% ground quartz by weight, 7–10% resin. The exact ratio varies by brand and by color within a brand. |
| Porosity | Effectively none. The resin fills what would otherwise be pore space, which is why quartz never needs sealing — not at install, not in ten years. |
| Hardness | The quartz mineral sits around 7 on the Mohs scale. The slab as a whole behaves slightly softer, because the resin between the crystals is the soft part. |
| Acid resistance | Good. Quartz does not etch the way marble does. Strong alkaline cleaners and solvents are the ones that damage the resin. |
| Heat | The weak point. Polymer resins begin to soften somewhere between 150°F and 300°F (65–149°C) depending on formulation. A pan off a medium-high burner clears that easily. |
| UV | Not for outdoors. The resin yellows and degrades under sustained sunlight. If you want an outdoor kitchen, look at porcelain or granite instead. |
Where it shines
- Kitchens where nobody wants a maintenance schedule
- Anyone who wants a consistent, predictable pattern across a whole job
- Bathrooms, laundry rooms, and anywhere that sees standing water
- White and light designs that would stain in natural stone
- Households with kids, where wine and juice are a matter of when, not if
Where it needs care
- Hot cookware straight from the burner or oven — use a trivet, every time
- Outdoor kitchens and sunrooms, where UV will yellow it
- Waterfall ends and seams, where pattern repeat can look manufactured
Heat is the one real weakness, and it is worth being blunt about it
People hear “harder than granite” and assume quartz is bulletproof. On scratches, near enough. On heat, no — and the difference is not close.
Granite formed above 1200°F in the earth’s crust. Nothing that happens on a home cooktop concerns it. Quartz is a different animal: the crystals are fine, but the resin holding them together starts to soften from about 150°F, and the damage shows up as a dull patch, a yellowed ring, or in the worst case a hairline crack where the slab expanded unevenly.
The honest test of how seriously to take this: every engineered quartz manufacturer we work with voids the warranty for heat damage. Cambria’s own care documentation calls for trivets and hot pads. When the people who made the slab put that in writing, it is not marketing caution — it is the actual limit of the material.
None of which makes it a bad choice. It makes it a choice with one rule attached, and it is an easy rule to keep.
Care and cleaning
You will never seal this counter
Not on day one, not in a decade. There is no pore structure to seal. If someone tries to sell you a quartz sealing service, that is the moment to stop the conversation.
Day to day, warm water and a mild dish soap on a soft cloth handles everything. For something dried on, a plastic scraper and a non-abrasive cream cleaner will lift it without marking the surface.
What to keep away from it
- Strong alkalis. Oven cleaner, drain cleaner, and high-pH degreasers attack the resin. This is the opposite of the marble problem — acid is not the enemy here, caustic is.
- Solvents. Paint thinner, acetone, nail-polish remover. If a spill happens, flush it with water quickly rather than letting it sit.
- Abrasive pads. Steel wool and scouring pads will dull a polished finish permanently.
- Bleach left to stand. A wipe-and-rinse is fine. A bleach-soaked cloth left overnight is not.
Quartz is not quartzite, and the difference is expensive
These two get confused constantly, including by people selling them. The names are nearly identical and the materials have almost nothing in common.
Quartz is the manufactured composite on this page — crushed mineral in resin, made in a factory to a repeatable recipe. Quartzite is a natural metamorphic rock, quarried in blocks, no two slabs alike. Quartzite handles heat above 1200°F and can go outdoors; quartz does neither. Quartz never needs sealing; quartzite does.
If someone shows you a slab and calls it “quartz” while describing natural veining and one-of-a-kind movement, ask which one they actually mean before you sign anything. We wrote up the natural stone in detail on our quartzite countertops page, including the industry’s ongoing problem with slabs sold as quartzite that are really something softer.
How we fabricate it
Quartz is templated digitally, cut on the SawJet, and edged and polished in our Everett shop by the same team that installs it. Because the material is manufactured, color and pattern are consistent from slab to slab within a batch — which makes it far more forgiving than natural stone when a job needs more than one slab.
Seams are the craft. On a busy pattern they disappear; on a solid white they are a matter of getting the cut, the fit, and the color-matched adhesive exactly right. We plan seam placement at template stage, not at install, so you know where it lands before anything is cut.
Finishes and slab sizes
Most quartz comes in a standard slab around 120″ × 55″, with jumbo sizes near 130″ × 65″ from the major brands. Jumbo slabs are worth asking about on any island over about ten feet, because they can turn a two-piece top with a seam into a single piece without one.
Finishes
| Polished | The standard. High gloss, deepest color, easiest to wipe clean. Shows fingerprints on dark colors. |
|---|---|
| Honed / matte | Soft, low-sheen. Beautiful in a modern kitchen. Shows fingerprints and oils more readily than polished, and marks show up sooner on dark colors. |
| Textured / leathered | Available on a limited range. Hides fingerprints better than either of the above. |
Not every color is offered in every finish. Bring us the brand and color you are considering and we will tell you what is actually available before you fall for a sample.