By Pennie L. Sabel and
Mark Haverstock

Just as the butterfly metamorphoses from a caterpillar, quartzite was transformed from grainy quartz-rich sandstone, although it took 500 hundred million years or more to accomplish the latter. Quartzite is a metamorphic rock heated under pressure deep within the earth's mantle where the original quartz sand grains and quartz silica cement became fused into one.

Quartzite has a rich crystallized appearance and is hard, compact and very fine-grained. Most varieties of quartzite contain at least 90 percent quartz and are the largest and purest concentrations of silica in the earth's crust. Normally quartzite is white or light grey, but it may be found in a variety of other colors including yellow, light brown, blue, green, purple, black, shades of pink or red depending on the other minerals such as mica, tourmaline, zircon or iron oxide that may be present.

Unlike sandstone, quartzite breaks through, not around the quartz grains and produces a smooth surface rather than a rough and granular one. Sandstone will shatter into many individual grains of sand, while quartzite breaks into sharp angular fragments — the crystallization of the quartzite makes it harder. It is one of nature's most durable stones — non-porous and highly resistant to weathering.

	St. Lawerence University Dana Dining hall exterior and archway includes blend of ashlar, European ashlar. (Courtesy Champlain Stone)

In recent years quartzite's popularity has grown dramatically as a building and landscape material. Quartzite has been finding its way into major building projects, such as the Monterey Bay Aquarium in Monterey, California.

Quarrying
The bulk of quarrying in the United States occurs in Idaho and Utah. Other major quartzite operations are located in Wisconsin, New York, Pennsylvania, Minnesota, Montana, South Dakota, and Arizona. Europe, Africa, South America, India and China are primary international sources.

Typically quartzite is obtained by surface mining, since most deposits are either exposed or located near the surface. The stone is extracted by first removing any overburden from above the stone and it is then removed using large excavators. "We usually need to take five to six feet of soil off, and may have to blast through some rock until we get to material we can use," says Woody Mercer of Cumberland Valley Stone.

At times, explosives may be required to loosen the stone ledges. At Champlain Stone's site, the process begins with deep holes drilled at staggered depths from 4 to 35 feet into the ledge and about 12 feet from the edge of the natural ledge. Next, charges are placed into the holes. The detonation only bumps the stone away from the natural ledge — this way the stone mass is loosened, not blown into small pieces.

Drilling and feathers and wedges for plugging are used for breaking larger blocks into thin slabs. Miners will tap each wedge and continue down the stone until it begins to separate. Then the feathers and wedges are removed and a pry bar is used to finish separating the slab from the rest of the stone.

Splitting and Fabrication
Once removed from the quarry, the stone is either split manually or by machine. Machine processing is done by the guillotine, a hydraulic device which uses tooth-like chisels to snap quartzite into finished products such as ashlar or veneer stone. The stone moves by conveyor and is positioned by hand to be snapped. Further trimming is generally done by hand at the other end of the conveyor and is put into containers and transported to the packaging area.

	Private residence in Lake George, NY utilizes roughly squared/roughly rectangular South Bay Quartzite for walls and arch. (Courtesy Champlain Stone)

A more labor intensive method used by some quarries is to split stone by hand using hammers and chisels according to company specifications. Products produced by this method often include mosaic veneer, flagging, wall stone, uniform rise wall stone and thin wall stone. The final steps for both machine and hand-cut stone are to grade, stack and package onto pallets for shipment.

According to Jim Burch at Oakley Valley Stone in Oakley, Idaho, fabrication of quartzite has been slow to develop because of the stone's characteristics. This process is still limited to a handful of companies that have the necessary high-tech equipment to service customers and dealers. "Because of quartzite's hardness and mica content, it is difficult to cut," says Greg Osterhout of Northern Stone Supply, also located in Oakley, Idaho. "We have a polisher and a large bridge saw that lets us cut fireplace hearths and mantels."

Two South Bay Quartzite columns flank entrance to Queens Botanical Gardens. (Courtesy Champlain Stone)

To meet increasing customer demand for fabricated products, quartzite sheets are now being sawn into tiles that can be honed or polished. With the development of the water jet and better carving tools, decorative countertops and sinks are easier to construct. At Tennessee Building Stone in Crossville, Tennessee, David Rose says their fabrication process includes sawing, cutting, splitting, tumbling and other methods of finishing the stone that are required by his customers.

Companies like Cumberland Mountain Stone also offer options such as sandblasting. "A university wanted steps sandblasted because they were concerned about slip resistance," says Woody Mercer. "It also another option for the finish texture and customers now choose it for looks as well as safety."

Sometimes a minimalist approach is best. "The old theory in quarrying is to touch something once," says George Cannell of Delaware Quarries. "More processing means increased cost. If you're quarrying and get something that comes out as a boulder, you're not going to try to split it because you may not be happy with the end result. So you just sell it as a boulder." Lon Thomas of American Stone in Salt Lake City, Utah, says most of the quartzite sold by his company is broken, irregular flagstone and little fabrication is done except for tile products.

Private residence features South Bay Quartzite walls, steps slabs and exterior walls.
(Courtesy Champlain Stone)

Characteristics
Recognized for its strength and durability, quartzite has been used for many years in the construction of roadways and bridges as well as for railroad ballast and erosion control.

	Tall fireplace structure at Maine Bean Bakehouse and Deli, Windham, ME, utilizes mosaic TSV, giving appearance of full stone without the weight. (Courtesy Champlain Stone)

"Our quarry was originally opened to supply armor stone to the Army Corps of Engineers for shore erosion protection on the Great Lakes," says Moe Bohrer of Anderson Brothers & Johnson/Michels Corporation. "The reason the Corps of Engineers liked it was because of the low porosity — freeze-thaw cycles won't crack or degrade it." Railroads chose it as ballast for the same reason.

Unit weight of quartzite is nearly the same as granite at about 170 pounds per cubic foot as compared to sandstone at 125 to130 pounds per cubic foot. Denser means less water absorption — quartzite has less than a 1 percent absorption rate, yet sandstone can be as high as 14 percent. "You see a lot of applications for sandstone in the south as compared to the north where you'll see more granites and quartzites simply because of the freeze/thaw factor," says Bohrer.

Osterhout agrees that a major selling point for quartzite is its hardness and durability. "On the Moh's hardness scale it rates a seven, which is a very hard stone," he says. "It's impervious to stains and it doesn't wear significantly. Quartzite is really a lifetime product."

Quartzite is found naturally in two basic varieties. Both are metamorphic rock which started as sandstone, but their characteristics vary according to the amount of heat and/or pressure during formation. Orthoquartzite is very pure quartz sandstone composed of usually well-rounded quartz grains cemented by silica with only minor amounts of minerals. Metamorphic quartzite (meta-quartzite) features individual quartz grains that have crystallized together to form an interlocking mosaic of quartz crystals.

Applications
Quartzite is used in both residential and commercial applications and quite frequently in landscaping environments. It can be found in pool surrounds, patios, fountains, walls, paving and curbing as well as stairs and stepping stones. "Our South Bay Quartzite lends itself nicely to flagging because it's a very linear bed," says Jane Bennett of Champlain Stone. "The quarried pieces come up in large, thin slabs that lend themselves nicely to flagstone applications."

More Than Buildings In today's world, quartzite is primarily considered a building material. But this versatile rock has a history of varied and unusual applications dating back to our country's earliest inhabitants. About 12,000 years ago, Native Americans discovered quartzite. They began mining in the area now known as Silver Mound in Jackson County, Wisconsin, using the durable rock to make tools, spear points and other weapons. This group launched the first stone business in Wisconsin, trading finished tools and stone throughout the Midwest. Nearly 6,000 years later the Iowa, Arapaho, Cheyenne and Dakota tribes congregated in present-day southwestern Minnesota along a 25 mile-long stretch of quartzite bedrock. Now known as the Jeffers Petroglyphs Historic Site, this area served as a huge stone tablet — a collection of about 2000 Native American images that told the story of their survival and spiritual life over thousands of years. Stone retailers now realize there is money in quartzite, but West Africans actually used quartzite as money starting in the 17th century. The early disk-shaped currency was made from quartzite stones with cone-shaped holes drilled from both sides. Each piece was roughly two inches in diameter, weighing a little over three ounces. Asante legends suggest the stones fell from heaven and contained magical powers. Quartzite has also been used as a gemrock, particularly as a substitute for jade known as Indian jade. Red, blue and green adventurine, a quartzite containing minerals that add color, have a long history of use as beads, in rings, candle holders, statuary, and other decorative items.

John Bastovan of Peninsula Building Materials notes that the majority of their quartzite sales are for paving applications — patios and floors using cut pattern and random irregular pieces. "Quartzite is economical because it's naturally on the thin side, it comes in thinner sheets and you get better coverage," he says. "If you break it down by square footage, it is one of the least expensive yet durable paving stones."

Because of the hardness of the stone, it is well suited for use near water or potentially wet areas as the water doesn't penetrate discolor or scar the surface. Its non-skid texture makes it an ideal material for use around swimming pools, spas and high traffic flooring areas.

Thin veneer quartzite is typically used for interior or exterior walls and fireplace surrounds. Full quartzite veneers are utilized in building applications much the same as granite and limestone. Slabs up to 100 square feet are possible with this material — everything from fireplace mantel size to gargantuan components of an outdoor boulderscape. Quartzite boulders are sited in landscaping as accent pieces and are also used to create unique benches, seating areas and tables.

A Growing Market
As with other types of natural stone, the demand for quartzite is increasing. "Quartzite is outshining other types of stone and is expected to increase in a market share through the next several years," says Thomas. Rose predicts sawed and fabricated material becoming more popular, but the natural product will always have a big share of the quartzite market that he serves. Color trends in his market have shifted from pink shades to more earth tones as well as blues and grays.

"Overall, I would expect continued growth because of the inherent beauty, hardness and strength of natural quartzite," says Cannell. The only downside he sees at this point might be the increasing cost of labor and skyrocketing fuel prices, which lead to increased transportation costs.

Langhorne flagstone on palettes ready for shipping.
(Courtesy Delaware Quarries)

Osterhout maintains that demand for quartzite is twice the supply that is available. But much of the challenge of delivering the product comes from government regulations in the quarrying operation. He finds it frustrating to keep up with those regulations while at the same time planning for the future of the company. The quarries that his company operates are located mostly on public land and those operations require a lengthy permit process in order to expand. Located in Idaho, he says that he is also up against a "preserve the west" movement that would limit the use of public lands for these types of quarrying operations.

Quartzite may not be as well known as its more famous brothers and sisters — granites, marbles and limestones — but its unique characteristics of hardness, durability and its clean fine-grained texture make it the stone of choice for many challenging projects that require a different aesthetic appeal.

Credits:
Jane Bennett, Champlain Stone Ltd., P.O. Box 650, Warrensburg, NY 12885. 518-623-2902

Woody Mercer, Cumberland Valley Stone, division of Turner Brothers Stone, P.O. Box 297, Crossville, TN 38557. 800-334-7719

Jim Burch, Oakley Valley Stone, 204 West Main St., P.O. Box 284, Oakley, ID 83346. 208-862-3450

David Rose, Tennessee Building Stone Inc., 1313 Chestnut Hill Road, P.O. Box 2600, Crossville, TN 38557. 888-484-9121

Greg Osterhout, Northern Stone Supply Inc, P.O. Box 249, Oakley, ID 83346. 208-862-3353

George Cannell, Delaware Quarries Inc., 1868 West Superhighway, Langhorne, PA 19047. 215-862-1670

Lon Thomas, American Stone Inc., 4040 South 300 West, Salt Lake City, UT 84107. 801-262-4300

Moe Bohrer, Anderson Brothers and Johnson, division of Michels Crop., P.O. Box 128, Brownsville, WI 53006. 800-382-0700

John Bastovan, Peninsula Building Materials, 1175 Aster Ave., Sunnyvale, CA, 94086. 408-246-0550

References:
Dietrich, R.V., "Quartzite," http:// www.cst.cmich.edu/users/dietr1rv/quartzite.htm

The Jeffers Petroglyphs Historic Site, http://www.thudscave.com/petroglyphs/index2.htm

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