Roughly 90 Percent Crushed Quartz Bound in Polyester Resin
Engineered quartz is not a quarried slab. It is manufactured from 90 to 93 percent silica by weight, crushed quartz grits and powder running as pure as 99.9 percent, held in 7 to 10 percent unsaturated polyester resin with pigment added. By volume the split is closer to 66 percent quartz to 34 percent resin.
The forming step is what makes it work. The Bretonstone process, developed by Breton S.P.A. in Treviso, Italy, pours the mix into a mold and compacts it under vacuum while vibrating it, driving out the air voids that would be weak points. The pressed slab cures 24 to 48 hours before polishing. Standard thicknesses are 12mm, 20mm and 30mm.
That recipe explains almost every behavior below. Quartz gives hardness. Resin gives non-porosity and color control, and also sets the temperature ceiling and the UV limit.
Non-Porous by Manufacture, Which Is Why It Never Needs Sealing
Because the slab is vibrocompacted under vacuum, there is no connected pore network for liquid to enter. It is non-porous by manufacture rather than by treatment, which is why a quartz counter never needs sealing.
The result is the most discoloration-resistant surface we install. Wine, coffee, turmeric and cooking oil sit on top until you wipe them, and unsealed porous stone can harbour bacteria in a way a non-porous surface simply cannot.
What Still Damages It
Non-porous does not mean chemically immune. Drain cleaner, oven cleaner, paint stripper and bleach left sitting will dull or discolor the resin at the surface. Warm water and a pH-neutral cleaner handle everything normal.
Mohs 7 Hardness Against Marble’s 3
Quartz sits at about 7 on the Mohs scale. Marble sits at about 3. Four steps apart, on a scale where every step is a real jump.
A steel knife blade runs around 5.5, so it cannot scratch a Mohs 7 surface, which is why quartz survives someone slicing a lime on the counter. What does scratch it is anything harder: unglazed ceramic dish bottoms, grit tracked in on a pot, abrasive pads. One caveat we mention up front: the polyester binder keeps hardening over years, and that slow cure costs the slab a little flexural strength across a long life. It is why we do not skimp on support at cutouts and overhangs.
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The 300 Degree Resin Ceiling and Thermal Shock
Engineered quartz is unaffected below 150 degrees Celsius, which is 300 degrees Fahrenheit. Above that the resin binder is in trouble. It is meaningfully less heat resistant than granite, marble or limestone, and it is specifically vulnerable to sudden temperature change rather than steady warmth.
A cast iron skillet off a hot burner clears 300 F easily, and so does a stock pot off a rolling boil. Any of those can leave a permanent dull patch, a yellowed ring, or a hairline crack running out of a cutout corner. It is the most common quartz complaint we get called about and it is entirely preventable.
Practical Rules for a Quartz Kitchen
Trivets at the range, always. A board or mat under any small appliance that runs hot. If you are the household that pulls a sheet pan out and sets it down in one motion, say so at the estimate, because {{LINK:material:granite}} is the more honest fit.
UV Breakdown Rules Quartz Out of Uncovered Patios
Continuous ultraviolet exposure discolors engineered quartz and breaks down the resin binder. That is degradation of the material itself, not a maintenance issue you can get ahead of, and it makes quartz unsuitable outdoors. We do not install it on an uncovered patio and no reputable warranty covers it there.
Austin makes that a real decision, with about 2,650 hours of sunshine a year and July and August highs averaging above 95 F. Even a bright sunroom can shift color over years in the sun-lapped strip while the rest of the counter stays put. For anything that sees sky we specify {{LINK:material:porcelain}} or {{LINK:material:sintered-stone}}, both UV stable through the body, on every {{LINK:service:outdoor-kitchen-countertops}} project.
Color Consistency Across Multi-Slab Kitchens
The strongest argument for quartz is the one buyers underrate. Because the material is manufactured, a color is repeatable, so a kitchen needing three slabs reads as one continuous surface. Damage a piece in five years and the same color is usually still in production. Natural stone cannot promise that, so we lay a quartz slab beside a {{LINK:material:quartzite}} and let you decide with your eyes.
| Behavior | Engineered Quartz | Porcelain Slab | Granite | Solid Surface |
|---|---|---|---|---|
| Sealing required | Never | Never | Every five to ten years | Never |
| Direct heat | Poor, 300 F resin ceiling | Excellent | Excellent | Poor |
| UV stability outdoors | Not suitable, resin degrades | Suitable | Suitable | Not suitable |
| Scratch resistance | High, about Mohs 7 | Very high | High | Low, but sands out |
| Seam visibility | Tight, color-matched | Visible at the joint | Visible, pattern dependent | Sanded invisible |
| Color repeatability | Excellent across slabs | Good | None, natural variation | Excellent |
Wet Cutting and Silica Dust in the Shop
Cutting and polishing engineered stone releases respirable crystalline silica, and the trade has a genuine occupational disease problem because of it. Australia banned engineered stone outright on 1 July 2024 over worker silicosis. California adopted emergency regulations in December 2023, after around 500 fabrication workers were diagnosed and inspectors found 72 percent of shops out of compliance with federal silica standards. We cut wet and run dust control.
Where Quartz Is the Wrong Choice
Households that set hot pans down without thinking do better on natural stone, and anything outdoors needs a UV-stable body. If seams that vanish completely matter more than hardness, {{LINK:material:solid-surface}} does something quartz cannot, because its glued joints are sanded flat.
Where We Install Quartz Around Austin
We run quartz jobs across the metro weekly, from tract kitchens to gut remodels. That includes new builds throughout {{LINK:location:leander}}, kitchen and bath work in {{LINK:location:hutto}}, full replacements in {{LINK:location:kyle}} and island upgrades in {{LINK:location:buda}}. Accurate {{LINK:service:countertop-templating-and-measurement}} keeps a multi-slab quartz kitchen looking like one piece, and {{LINK:service:seamless-countertop-joining}} is where the craft shows.
Ready to compare colors in person? Browse every surface we fabricate at {{LINK:home}}, then call {{PHONE}} to book a free in-home measure with samples in hand.
Quartz Countertop Questions From Austin Homeowners
Is quartz better than granite?
Neither wins outright. Quartz is non-porous, never needs sealing, resists staining better than anything else we install and repeats its color across slabs. Granite tolerates heat far better and works outdoors. If your household sets hot pans down, choose granite. If you want a uniform kitchen with no maintenance, choose quartz.
Can quartz go outside?
No, and we will not install it there. Continuous UV exposure discolors the slab and breaks down the polyester binder holding it together, so the damage is to the material rather than the finish. For outdoor kitchens we specify porcelain, sintered stone or a UV-stable granite instead.
Does quartz scratch?
Rarely in normal use. At about Mohs 7 it is harder than a steel blade, so cutting on it dulls the knife rather than marking the counter. What does scratch it is harder grit: unglazed ceramic dish bottoms, sand tracked in from a job site, abrasive pads.
Why can’t I set a hot pot on quartz?
The resin binder is unaffected below 300 F and compromised above it, and quartz is vulnerable to sudden temperature change rather than gradual warmth. A skillet off a gas burner clears that number easily. The result is a dull mark, a yellow ring, or a hairline crack from a cutout corner.
Does quartz look artificial?
The current generation does not, in most colors. Modern veining is laid into the slab body rather than printed, so the pattern carries through a mitered edge. Where it can read flat is in the highest-drama marble imitations across a large island, because the repeat becomes visible.
Can chipped quartz be repaired?
Usually. A chip at an edge or a sink cutout is filled with color-matched resin, cured and polished flush, and on most colors it disappears at normal viewing distance. Thermal cracks running from a cutout corner are harder, and sometimes need a section replaced instead.