Got Data? Testing the Performance of Granite, Engineered Quartz, Concrete, and Sintered Countertop Surfaces

by | Nov 6, 2019 | Educate

Thank you to Dave Scott of Slabworks of Montana, and Tony Malisani of Malisani Inc., for preparing materials for these tests.

There is no shortage of opinions when it comes to countertop materials. We hear about granite being bulletproof and engineered quartz being low-maintenance but is that really true? Much of the information about various materials is either anecdotal or is published by the manufacturers and sellers of products. These sources of information may be spot-on… or perhaps not. It can be difficult to find reliable information about the practical properties of different types of countertop surfaces.

In a quest to bring more data-driven information to the countertop industry, this article offers side-by-side performance testing of four categories of materials. The purpose is twofold: to share test results from various countertop surfaces, and to illustrate how any material can be tested using these basic techniques. Bringing in a little more data to our industry helps everyone understand what to expect from particular products.

 

A Note About Objectivity

I’m an independent geologist, and I share the commitment of the Natural Stone Institute to bring educational information to the countertop industry, the design community, and consumers. It’s important to note that I didn’t pre-screen any of the materials used in this test. I picked a variety of colors, brands, and materials, ran the same tests on all of them, and documented all of the results. When I began the tests I did not know what the outcome would be. In an age where objectivity seems to be hard to come by, I did my best to remain unattached to any particular outcome. My motivation is to help people understand materials and be able to make informed choices, regardless of what type of material they are working with.

 

The Matchup: Materials Tested

To keep the tests manageable, I selected just one or two pieces from each type of countertop material. The article, Do Engineered Quartz Countertops Stain?, contains many more test results of staining, cleaning, and scrubbing.

Natural stone samples

  • Absolute Black granite with a bush hammered and brushed finish. Sealed with 2 coats of Dry Treat Stain Proof impregnating sealer
  • Thunder White granite (also known as Andromeda White) with a polished finish and sealed with 2 coats of Dry Treat Stain Proof impregnating sealer

Engineered quartz

  • Caesarstone Eggshell, polished finish
  • Sequel Pure Black, polished finish

Sintered surface (a heated and highly compressed blend of clays, feldspars, silica, and other minerals)

  • Dekton Trillium, which has an uneven, ‘distressed’ finish

Concrete

  • Poured concrete with gravel aggregate, ground flat and smooth, then sealed with Terra Glaze acrylic polymer sealer

 

The Tests

Hardness

Hardness is the ability of a material to withstand being scratched. It’s a relatively easy property to measure, using metal picks that are calibrated to Mohs hardness scale. Even though Mohs scale was developed to test individual minerals, it’s still a reasonable way to compare the overall hardness of different surfaces. The higher the number, the more the material will stand up to the affronts of metal utensils, cast iron cookware, and roasting pans being slid along the surface.

The sintered surface from Dekton ultimately ranked the hardest material in the test, with a Mohs hardness value between 7 and 8, meaning it’s harder than both glass and steel. The two granites were next in line, with values between 6 and 7. That result makes sense considering the two most common minerals in granite are feldspar and quartz, which rate 6 and 7 on the Mohs hardness scale, respectively. Engineered quartz product Caesarstone Eggshell was slightly softer than granite and was more readily scratched by the #6 hardness pick. Sequel Pure Black was easily scratched by the #6 tool, putting its hardness slightly below 6. The glossy black color of that manufactured quartz material also made the scratches easy to see.

Left: Sequel Pure Black engineered quartz has a Mohs hardness less than 6; the #6 hardness tool can scratch it, as shown here.
Right: Dekton Trillium has a hardness greater than 7, but less than 8. It was the hardest material in the test.

The softest material in the test was concrete. The matrix had a hardness around 4, and the different types of stone aggregate had measured hardness values ranging from 5 to 7.

 

Acid resistance

Next I tested each sample for its ability to withstand acidic liquids by putting about 1/4 tsp of white vinegar and two droplets of 10% diluted hydrochloric acid on the samples, allowing the acids to sit on the samples for 30 minutes. Diluted hydrochloric acid is the standard method geologists use to identify acid-susceptible stones. After the 30-minute period, the samples were then cleaned with soap and water, towel-dried off, and inspected. There were no visible effects on any of the materials except concrete.

While the acids were sitting on the concrete, a bubbling chemical reaction was clearly visible with the hydrochloric acid, and a slight bubbling reaction could be seen in the vinegar when using a magnifying glass. These reactions indicate that the acids were dissolving the carbonate minerals in the concrete. Once the acids were wiped off, the hydrochloric acid left a pitted area where the surface had been etched. No etching was visible from the vinegar, perhaps because the surface was somewhat rough and non-glossy to begin with.

 

Staining and cleaning

The ability for countertops to repel stains is a high priority for commercial property owners and homeowners, and it’s hard to predict what types of substances people will put on their countertops. I tested the stain-resistance of the samples with three common substances known to cause stubborn stains: turmeric, food coloring, and permanent marker.

For the test, approximately ¼ tsp of turmeric paste (a mixture of powdered turmeric and water), and two droplets of food dye were placed on each sample. These were left to sit on the samples for two hours, then cleaned off with mild soap and an ordinary kitchen sponge.

The dark colored materials – Absolute Black granite, Sequel Pure Black engineered quartz, and Dekton Trillium sintered surface material – did not endure any visible stains from turmeric or food dye, which speaks well to the ability of a material’s color and pattern to mask blemishes. Throughout all the testing I have done, darker materials and busier patterns are generally more effective at hiding stains.

The Thunder White granite showed very faint stains from food coloring, and these were easily removed with further cleaning with a kitchen sponge and mild dish soap. Thunder White also showed a moderate stain from turmeric, which faded overnight and was only visible because I knew exactly where to look. An observer did not see any stains on the white stone. Over the next 24 hours, the stain faded away completely.

Caesarstone’s Eggshell engineered quartz had moderate stains from both the turmeric paste and food coloring. As I continued to scrub and clean the quartz, the stains lightened, but did not disappear completely. The next day, the stains had faded somewhat, and the only plainly visible stain was from the food coloring.

Concrete was severely stained by both the dye and the turmeric, and further cleaning was only minimally effective at reducing the stains.

Left: Caesarstone Eggshell engineered quartz was stained by blue food dye, pink food dye, and turmeric paste.
Right: The same stains after further cleaning with mild soap and scrubber side of kitchen sponge.

Removing permanent marker

A Sharpie™ brand permanent marker left an obvious mark on all of the samples tested. The marker stain was most easily removed from Thunder White granite, requiring only mild soap and a kitchen sponge. On all other samples except concrete, non-acetone nail polish remover was required to successfully clean the marker stain.

On the concrete, nail polish remover was able to remove Sharpie™ marker that had just been applied, but did not remove dried on marker stains. Soft Scrub™ brand cleanser appeared to be the most effective at removing the marker from concrete, but it only lightened the stain; it did not remove it.

 

Scrubbing with abrasives

Abrasive cleaning products offer a challenge for some countertop surfaces. Several quartz manufacturers advise their customers to steer clear of abrasives, and for good reason. Abrasives have the potential to dull the finish of manufactured quartz because the resin that binds the quartz particles together is considerably softer than the particles of mineral quartz aggregate that are used in engineered stone.

In this test, two brand name cleaning products were used, Soft Scrub™ with Oxi, and Bar Keepers Friend™. These were applied with an ordinary kitchen sponge with a nylon scrubbing surface, and 30 seconds of vigorous scrubbing.

Soft Scrub™ uses the mineral calcite as its abrasive agent, and calcite is a mild abrasive with a Mohs hardness of 3. The Soft Scrub™ left a very subtle hazing on the Sequel Pure Black engineered quartz. The black color and glossy finish is an unforgiving surface when it comes to hiding imperfections.

The Thunder White and Absolute Black granites, Dekton Trillium sintered surface, and Caesarstone Eggshell engineered quartz did not have any visible effects from the Soft Scrub™.

Concrete became visibly dulled after using Soft Scrub™. It appeared that the satin shine from the applied sealer was removed, and the effect was easily noticeable.

Bar Keepers Friend™ is a more robust abrasive cleanser containing feldspar, which has a Mohs hardness around 6. Thirty seconds of scrubbing with Bar Keepers Friend™ left distinct hazy areas on both of the engineered quartz samples. The Dekton and natural stone samples were unaffected. The concrete was significantly dulled from the Bar Keepers Friend™, and in fact I could feel the material becoming rough and abraded as I scrubbed.

 

Heat resistance

Heat impacts surfaces in a few different ways. The thermal shock of sudden heating of a cool surface has been known to break slabs. Furthermore, heat can scorch or discolor materials that have low melting temperatures. Kitchen countertops are exposed to heat in several ways, from being adjacent to stoves and dishwashers, to the potential for having hot pans placed directly on top of them. It’s important to note that quartz manufacturers specifically warn against putting hot pans directly on their surfaces, and thus, the precaution of “don’t try this at home” applies to this test.

Left: The setup for hot, oily skillet test on Caesarstone Eggshell manufactured quartz. Mongolian Fire Oil is on the left, Texas Pete hot sauce on the right.
Right: Hot, oily skillet test underway on concrete. The skillet was heated to 575 degrees F, and placed on the slab for 10 minutes.

I tested heat resistance in two different ways. I placed a very hot cast iron skillet on top of the samples and let it sit for 10 minutes. The skillet weighed 3.5 pounds and had a footprint of 6.5 inches where it contacted the slabs, and was heated to about 570 degrees F.

The hot, dry skillet test left a temporary, light colored mark on the Sequel Pure Black sample, but the mark wiped off. No other test sample surface showed visible effects from that test.

Then, I took it up a notch with the hot, oily skillet test. This is a tough one: the surface of each of the slabs was first sprinkled with Mongolian Fire Oil and Texas Pete brand hot sauce, and the hot skillet was placed on top of the oily surface. This test represents a worst-case scenario where a hot pan is placed on a dirty countertop. While it is certainly not recommended to treat one’s countertop this way, it’s easily within the range of possibility – homeowners, guests, renters, or contractors are not always familiar with the exact properties of a countertop, and errant moves with hot pans do happen.

Dekton’s Trillium sintered surface showed no effects from this test, but every other material had some sort of noticeable change. Thunder White granite showed a slight stain from the hot oil, but the stain faded over 24 hours, to the point where it was invisible. Absolute Black granite exhibited a very subtle darkening of the surface in the area where the skillet had been sitting. This change was so slight that observers could not see it unless I pointed it out.

The Caesarstone Eggshell engineered quartz sample was stained by the hot oil, and initially there was a curved stain in the shape of the skillet, as well as a stain in the center of the area where the skillet had been. By the next day, the curved stain had faded, but the other stain remained. Over the course of several days, the stain lightened further, to the point where it was no longer visible.

The finish of Sequel Pure Black engineered quartz became slightly hazed and lighter in color in the area where the skillet had been sitting. The mark remained permanent.

Concrete was severely stained by the hot, oily skillet test. The stain covered most of the area that had been underneath the skillet, and while the stain faded slightly overnight, it was still large and prominent.

From Left to Right:
Thunder White granite after the hot, oily skillet test and before cleaning.
Damage on Sequel Pure Black manufactured quartz from the hot, oily skillet test (foreground) and from Bar Keepers Friend (background).
Concrete was damaged by all but one of the tests. The sample was pretty beat up by the end of the analysis.

 

TL;DR – The quick summary

Two materials exited the tests looking the same way they came in: Thunder White Granite and Dekton’s Trillium sintered surface. Thunder White shrugged off Sharpie™ marker better than any other material, but the stone’s light color revealed slight, temporary staining from hot oil and turmeric. No permanent stains persisted after cleaning, and neither heat nor abrasives affected the stone’s brightly polished surface.

The sample of Dekton Trillium was unfazed by any of the tests. In part, this product is made of materials that resist staining and scratching, and in part, its dark color and uneven surface finish made it hard to spot discoloration or damage. That’s why I was careful to note the degree of visible effects – it turned out that the variations of each material’s color and finish played a role in the way it either masked or revealed different types of damage. Nonetheless, Dekton is clearly a strong performer and I’m curious to do more testing of this relative newcomer and investigate properties such as chipping or cracking.

Absolute Black granite sailed through every test except the hot, oily skillet, which darkened the surface in a subtle way that observers did not notice unless prompted where to look.

The two samples of manufactured quartz each had slight to moderate damage from the tests. The Caesarstone Eggshell was stained by food coloring, turmeric, and hot oil. Over time the turmeric and oil stains faded, while the food coloring persisted. Sequel Pure Black was more susceptible to scratching, and showed some hazing when exposed to high heat. Both types of engineered quartz became dulled when scrubbed with Barkeepers Friend.

Far and away, the concrete suffered the most damage from these tests. Concrete is porous, and that’s what allows stains to penetrate. The cement that binds concrete together contains calcite (calcium carbonate), and thus cement will etch from acids. Lastly, concrete is soft and prone to scratching. This is not to say that concrete should be ruled out as a useful material, but it’s paramount that clients fully understand the properties and performance of concrete before committing to it.

 

Performance matters

If you’ve read this far, you now know more about countertop performance than most people, so congratulations!

So what’s the bottom line? First and foremost, think about the priorities and details of your specific situation. Is staining likely to be a problem? What about mishaps with hot pans? Do you tend to over-scrub a surface and are worried about damaging the finish? Use the test results that are most relevant to your needs.

Secondly, it’s a great idea to try some of these tests on any product you are considering, whether you are a homeowner or an industry pro. That will give you the most specific information, and you’ll continue to broaden your understanding when you interact with a material. Don’t be afraid to ask your countertop supplier for samples.

How does natural stone fit into all of this? The granite samples stood up very well to the abuses of these tests. Both Absolute Black and Thunder White generally outperformed engineered quartz, they were head and shoulders better than concrete, and they were comparable to Dekton. That’s good news to fans of natural stone – although be sure to investigate your particular material whenever possible.

A vast array of different products, colors, and styles are available for countertops today. Selecting materials can be a dizzying choice, but usually comes down to the same question: Are its properties a good match for your situation? When in doubt, zero in on how a material behaves and performs, try some tests, and learn as much as you can. In an environment steeped in hearsay and marketing copy, real world information will always be your ally.

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