Last Updated: Jan 19, 2022
Among the many surfaces available for such hard-working areas of the house as bath and kitchen countertops, engineered quartz may hold the most cache. Expensive, durable, and nonporous, homeowners often choose engineered quartz for its beauty (it looks like natural stone). It's also scratch and stain-resistant, unlike marble. Granite, another popular and expensive choice, can crack and requires periodic sealing. In addition to being heat- and water-resistant, engineered stone also doesn't require sealing. It's virtually maintenance-free.
While the texture, color, pattern, and veining of natural stone can vary from slab to slab, engineered quartz is highly consistent. Made from natural quartz (from 93 to 96 percent) combined with epoxy or polyester resin as a binder, engineered quartz "doesn't contain toxic chemicals," according to Joel Hirshberg, the founder of Green Building Supply. "All are NSF certified." And that's important from a health and safety perspective. According to NSF.org, NSF certification is not a one-time initiative. It requires regular on-site inspections of facilities and routine re-testing of products. These ongoing actions ensure that they continue to meet the high standards necessary to maintain the certification.
For all of these reasons, engineered quartz is a trendy choice, especially among homeowners who can afford it. But beyond being low-maintenance and durable, how sustainable is it?
M S International (MSI), a national distributor of floor, wall, and countertop surfaces, touts quartz as inherently eco-friendly because most of its composition is from the earth. There's a nice sentiment, but there's more to the sustainability story, including extracting and fabricating the quartz into countertops.
Quartz isn't a renewable resource, but it's also not in short supply. Quartz is the most common mineral in the earth's crust. The Minerals Education Coalition tells us that quartz is a chemical compound of silicon dioxide (or silica, SiO2) with a crystalline form (hexagonal). They say that quartz is found in all types of rocks, be they metamorphic, sedimentary, or igneous. Quartz, as a material, is resistant to weathering.
However, the environmental impacts of mining are significant. These impacts include:
Consider also the petroleum products used in mining and transporting quartz for manufacturing. Quartz used for industries in the US (including in the manufacturing of clocks, computers, and radios) is mined in Arkansas, Virginia, North Carolina, and California. According to American Mineralogist, it's also mined in Brazil, Australia, Guatemala, Columbia, and Madagascar. Petroleum products are used in the fabrication process and in the resins that hold the items together.
The major companies creating engineered quartz include Cambria in Minnesota; Silestone, based in Spain; and Caesarstone, headquartered in Israel.
At the Cambria manufacturing facility in Belle Plaine, Minnesota, we learned the family-owned company started after purchasing a failed quartz-countertop business in northern Minnesota called Technimar Industries. The deal included the processes of Italian inventor Marcello Toncelli. Toncellis had developed a method to mass-produce engineered stone out of quartz, in whatever amount was required, with the same color and with the same structure, at the touch of a button. He made the quartz surfaces using machines he invented, including vibro-compression under vacuum, a patented technology used today by most engineered-stone manufacturers, including Cambria.
To keep up with demand, the plant runs 24/7. The manufacturing process begins when pure quartz is delivered from quarries throughout North America in large bags. After inspection of each bag, samples are sent to the lab upstairs for testing. In this lab, technicians also experiment with colors and patterns and test random samples of finished slabs for abrasion, strength on impact, and breakage.
After the lab approves a bag of quartz, workers ticket the bag for use in production. Cambria uses quartz in different sizes, so particles fit together when the quartz is compacted, slabs are free of voids, and the finished material is nonporous. The finest grade of quartz, which has an almost flour-like consistency, arrives in bulk tanks and is transferred into large steel silos in an enclosed room.
Over the years, Cambria's research-and-development team has refined Toncelli's touch-of-a-button process to ensure consistency in color, pattern, and quality in each of the designs. The recipe for a batch of Cambria, which produces about ten slabs, is entered into a computer. This mixture, composed of 93-percent quartz, is weighed and drawn from various-size hoppers, then poured into an enormous mixer with a liquid binder that comprises the final seven percent.
Next, they add a colorant. Once mixed, the dry, pliable material—now the consistency of cookie dough—is dumped onto a conveyor, which dribbles the material onto a large black rubber mat with turned-up edges. The machine places a similar rubber mat on top. The slab then goes into the press, where it's subjected to compaction vibration under a vacuum. This compaction pulls out all the air and compresses the mixture.
Throughout production, workers monitor the automated process on computer screens. They remove the slab's top cover when compaction is done and check each slab by touching its surface to ensure correct consistency. They then shove the slab into one of the shelves of a massive oven for curing. Once cured, the product is transferred to an area where a machine trims the slab's ends and sides and shaves a thin layer off the top and bottom.
The slab then enters the polishing machine. Water sprays the slab continually during polishing to keep dust to a minimum and cool and preserve the polishing tools. Water systems buried beneath the polishing lines capture, filter, and reuse all of the water.
Once polished, the slab is transferred to an inspection area. Workers check each piece for scratches, impurities, veining, and pattern, working off of a "standard," a proven, perfect slab they match against. Once approved, each slab receives an inventory-tracking bar code on a tag affixed to one end. A giant automated arm moving on a steel ceiling armature picks up and stacks the slabs for pickup.
The slabs are then cut into the precise profiles or shapes for the installers and inspected again. Inside large metal boxes, automated high-pressure water jets cut the curved edges of the profiles; precision blades cut the straight lines. In the finishing area, workers cut custom edges using hand chisels for a rough-stone look. Nearby, workers use clamps with vacuum pads to dry-fit every job's profiles together to simulate a job's installation.
The job's pieces are then set up on tables at the back of the facility for inspection. They look for defects related to fabrication, polish, and size per the installer's specifications in the job packet. Cardboard faces are cut to cover and protect the profiles; each piece is taped up, labeled, and readied for pickup.
Is this a "sustainable" manufacturing process? As with any judgment, you have to ask, "compared to what?" It certainly requires much more energy and water than some competing products, such as reclaimed wood countertops—which are not manufactured. Other countertops blend durability with greater sustainability and lower environmental footprint, such as those made from recycled paper (Paperstone or Richlite) or recycled glass. These "manufactured" countertops also provide durability but are made up of recycled or reused content—and may end up being recycled again at the end of their lives.
From a sustainability standpoint, when it comes to choosing the best materials, homeowners need to choose based on what is most important to them, personally. Is durability the most important aspect? Durability may not matter that much if you don't have a long time horizon—so if it will be replaced, can it be recycled? Is it the energy intensity of the manufacturing process that matters most? And is that energy coming from renewable sources like wind, hydro, or solar? Or is it the mining, harvesting, or collecting of the raw material itself? There are many considerations to take into account, and there is no one correct answer.
A premium countertop, engineered quartz has a deep, rich, stone-like appearance and a rock-solid feel. While it possesses several sustainable aspects, beauty—when sustainability concerns are considered—is genuinely in the beholder's eye.
Camille LeFevre is an architecture and design writer based in the Twin Cities.