Dimension Stone - Major Applications

Major Applications

While common colors used in some of the major applications are listed below, there is an extraordinarily wide range of colours, available in thousands of patterns. These patterns are created by geological phenomena such as mineral grains, inclusions, veins, cavity fillings, blebs, and streaks. In addition, rocks and stones not normally classed as dimension stone are sometimes selected for these applications. These can included tiles made of jade, agate, and jasper.

Stone (usually granite) countertops and bathroom vanities both involve a finished slab of stone, usually polished but sometimes with another finish (such as honed or sandblasted). Industry standard thicknesses in the United States are 3/4" (2 cm) and 1.25" (3 cm). Often 2 cm slabs will be laminated at the edge to create the appearance of a thicker edge profile. The slabs are cut to fit the top of the kitchen or bathroom cabinet, by measuring, templating or digital templating. Countertop slabs are commonly sawn from rough blocks of stone by reciprocating gangsaws using steel shot as abrasive. More modern technology utilizes diamond wire saws which use less water and energy. Multi-wire saws with as many as 60 wires can slab a block in less than two hours. The slabs are finished (i.e., polished, honed), then sealed with resin to fill micro-fissures and surface imperfections typically due to the loss of poorly bonded elements such as biotite. The fabricators shop cuts these slabs down to final size and finishes the edges with equipment such as hand-held routers, grinders, CNC equipment, or polishers. There has been a recent (2008) hubbub about radon emission from granite countertops; the National Safety Council states that the contributions of radon to inside air come from the soil and rock around the residence (69%), the outdoor air and the water supply (28%), and only 2.5% from all building materials-including granite countertops. A concerned homeowner can employ ASTM radon mitigation and removal techniques. The stone for countertops or vanities is usually granite, but often is marble (especially for vanity tops), and sometimes limestone or slate. The majority of the stone for this application is produced in Brazil, Italy, and China.

Tile is a thin modular stone unit, commonly 12 in. square (30.5 cm) and 3/8 in. (10 mm) deep. Other popular sizes are 15 in. square (38 cm), 18 in. square (46 cm), and 24 in. square (61 cm); these will usually be deeper than the 12 in. square. The majority of tile has a polished finish, but other finishes such as honed are becoming more common. Almost all stone tile is mass-produced by automated tile lines to identical size, finish, and close tolerances. Exceptions include slate flooring tile and special orders: tile with odd sizes or shapes, unusual finishes, or inlay work. In summary, the automated tile line is a complicated complex of cutting and calibrating machines, honing-polishing machines, edging machines that put on flat or rounded edges, and interconnecting conveyors to move the stone from the slab input to the final tile product. The stone for tiles is most commonly marble, but often is granite, and sometimes limestone, slate, or quartz-based stone. Common colors are white and light earth colors. Much of the stone for this application is produced in Italy and China.

Stone monuments include tombstones, grave markers or as mausoleums. After being gangsawed into big deep (up to 10 ft (3.0 m). wide and over 6 in. deep) slabs, smaller saws or guillotines (they break the granite and make the rough edges commonly seen on monuments) shape the monuments. The fronts and backs are usually polished. The individual monuments are then carved, shaped, and further defined by hand tools and sandblasting equipment. At this time, the stone for monuments is most commonly granite, sometimes marble (as in military cemeteries), and rarely others. An old rose quartz tombstone stands in a Harpers Ferry cemetery. Sandstone was common in the nineteenth century but is no longer used due to rapid rates of erosion. Most common monument colors for granite are gray, then black, then mahogany; for marble it is white. Today, the majority of the stone used in North America in this application is imported from countries such as India and China. This has depressed traditional North American monument centers such as Georgia and Quebec.

There are a number of smaller applications for buildings and traffic-related uses. Building components include stone used as veneer (exterior), ashlar, or other shapes. Veneer is a non load-bearing facing of stone attached to a backing, of an ornamental nature though it protects and insulates. Ashlar is a square block of stone, often brick-sized, for facing of walls (primarily exterior). The other shapes are rectangular blocks used for stair treads, sills, and coping (coping is sometimes nonrectangular). The shapes subject to foot traffic will usually have an abrasive finish such as honed or sandblasted. The stone is mostly limestone, but often is quartz-based stone (sandstone), or even marble or granite. Roofing slate is a thin-split shingle-sized piece of slate, and when in place forms the most permanent kind of roof; slate is also used as countertops and flooring tile. Traffic-related stone is that which is used for curbing (vehicular) and flagstone (pedestrian). Curbing is thin stone slabs used along streets or highways to maintain the integrity of sidewalks and borders. Flagstone is a shallow naturally irregular-edged slab of stone, sometimes sawed into a rectangular shape, used as paving (almost always pedestrian). For curbing, the stone is almost always granite, and for flagstone the stone is almost always quartz-based stone (sandstone or quartzite).

There are several other applications resembling flagstone in using rough dimension (or crushed) stone, usually as quarried, sometimes made smaller (i.e. by a jackhammer), often simply put in place: dry stone and riprap.

The stone used in these applications usually has to have certain properties, or meet a standard specification. The American Society for Testing and Materials (ASTM) has such specifications for granite, marble, limestone, quartz-based dimension stone (C616), slate (C629), travertine (C1527), and serpentine (C1526).