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14|February 2020
Got Data? Testing the Performance of Granite, Engineered
Slippery rock Gazette
Quartz, Concrete, and Sintered Countertop Surfaces
There is no shortage of opinions when it comes to countertop materials. We hear about granite being bul- letproof and engineered quartz being low-maintenance, but is that really true? Much of the informa- tion 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 da- ta-driven information to the coun- tertop industry, this article offers side-by-side performance testing of four categories of materials. The purpose is twofold: to share test results from various counter- top surfaces, and to illustrate how any material can be tested using these basic techniques. Bringing in a little more data to our indus- try 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 col- ors, brands, and materials, ran the same tests on all of them, and doc- umented all of the results. When I began the tests I did not know
Karin Kirk
usenaturalstone.com
Thank you to Dave Scott of Slabworks of Montana, and Tony Malisani of Malisani Inc., for preparing materials for these tests.
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 particu- lar 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 ma- terial. The article, Do Engineered Quartz Countertops Stain?, con- tains many more test results of staining, cleaning, and scrubbing.
Natural Stone Samples
• Absolute Black granite with a bush hammered and brushed fin- ish. 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 com- pressed blend of clays, feldspars, silica, and other minerals)
Dekton Trillium
This sample features an uneven, ‘distressed’ finish
Concrete
Poured concrete with gravel ag- gregate, 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 sur- faces. 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
Dekton Trillium has a hardness greater than 7, but less than 8. It was the hardest material in the test.
Sequel Pure Black engineered quartz has a Mohs hardness less than 6; the #6 hardness tool can scratch it, as shown here.
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 miner- als in granite are feldspar and quartz, which rate 6 and 7 on the Mohs hardness scale, respec- tively. Engineered quartz product Caesarstone Eggshell was slightly softer than granite and was more readily scratched by the #6 hard- ness 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.
Above: Sequel Pure Black en- gineered quartz tested at a Mohs
hardness of less than 6; the #6 hardness tool can scratch it, as shown here.
Top: 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 differ- ent 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 visi- ble effects on any of the materials except concrete.
Left: The sintered surface from Dekton ultimately ranked the hardest mate- rial in the test, with a Mohs hardness value between 7 and 8, meaning it’s harder than both glass and steel. The softest material tested was concrete.
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