Dimension stone is natural stone or rock that has been selected and finished (e.g., trimmed, cut, drilled or ground) to specific sizes or shapes. Color, texture and pattern, and surface finish of the stone are also normal requirements. Another important selection criterion is durability: the time measure of the ability of dimension stone to endure and to maintain its essential and distinctive characteristics of strength, resistance to decay, and appearance.ASTM, C18, C119-08 Standard Terminology Relating to Dimension Stone", ASTM, 2008, p.8
Quarries that produce dimension stone or crushed stone (used as construction aggregate) are interconvertible. Since most quarries can produce either one, a crushed stone quarry can be converted to dimension stone production. However, first the stone shattered by heavy and indiscriminate blasting must be removed. Dimension stone is separated by more precise and delicate techniques, such as diamond wire saws, diamond belt saws, burners (jet-piercers),Description of a jet piercing drill, TheFreeDictionary or light and selective blasting with detonating cord, a weak explosive.
Stone and rock types
A variety of igneous, metamorphic, and sedimentary rocks are used as structural and decorative dimension stone. These rock types are more commonly known as granite, limestone, marble, travertine, quartz-based stone (sandstone, quartzite) and slate. Other varieties of dimension stone that are normally considered to be special minor types include alabaster (massive gypsum), soapstone (massive talc), serpentine and various products fashioned from natural stone.ASTM, C18 "C119-06 Standard Terminology Relating to Dimension Stone", ASTM, 2007, pp. 11-13 | Types of Stones by Group|
A variety of finishes can be applied to dimension stone to achieve diverse architectural and aesthetic effects. These finishes include, but are not limited to, the following. A polished finish gives the surface a high luster and strong reflection of incident light (almost mirror-like). A honed finish provides a smooth, satin-like ("eggshell"), nonreflective surface. More textured finishes include brush-hammered, sandblasted, and thermal. A brush-hammered finish, similar to a houndstooth pattern, creates a rough, but uniformly patterned surface with impact tools varying in coarseness. A sandblasted surface provides an irregular pitted surface by impacting sand or metal particles at high velocity against a stone surface. A thermal (or flamed) finish produces a textured, nonreflective surface with only a few reflections from cleavage faces, by applying a high-temperature flame. This finish may change the natural color of the stone depending on mineralogical composition, particularly with stones containing higher levels of iron.ASTM, C18 "C119-06 Standard Terminology Relating to Dimension Stone", ASTM, 2007, pp. 9-10 |Types of Stone Finishes|
The most easily accessible general (non-graphic) references are the latest Minerals Yearbook Chapter (production and foreign trade, with statistics), and the latest (Issue 31) Dimension Stone Advocate News (new "building green" developments and demand statistics); see below. The most comprehensive, graphic references are Natural Stone Database by Abraxas Verlag (www.natural-stone-database.com), "Dimension Stones of the World, Volumes I & II" (Marble Institute of America) and "Natural Stones Worldwide CD" .
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 include 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 . Often 19 mm 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. In 2008, concerns were raised regarding radon emissions 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.ASTM, E06, "E2121-08 Standard Practice for Installing Radon Mitigation Systems in Existing Low-Rise Residential Buildings", ASTM, 2008, pp. 644-656 The stone for countertops or vanities is usually granite, but often is marble (especially for vanity tops), and is 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 square and deep. Other popular sizes are square, square, and square; these will usually be deeper than the 12-inch 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 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 wide and over 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. Granite and quartz both demonstrate good durability, especially because rain is naturally acidic. (This is a natural consequence of the carbon dioxide present in the atmosphere, which generates a weak solution of carbonic acid in rainfall; further acidification of rainfall arises from oxides of sulphur and nitrogen due to anthropogenic emissions). (Limestone and sandstone were commonly chosen for monuments in the nineteenth century, but they are no widely longer used because of the rapid erosion rates due to dissolution of acid-vulnerable carbonates by acidic rainfall.) The most common monument colors for granite are gray, black, and mahogany; for marble, white is most popular. 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, a non load-bearing facing of stone attached to a backing of an ornamental nature, although it also protects and insulates; and ashlar, a squared block of stone, often brick-sized, for facing of walls (primarily exterior). Other shapes include 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).L. Mead and G.S. Austin "Dimension Stone", Industrial Minerals and Rocks, 7th Edition, Littleton CO: AIME-Society of Mining Engineers, 2005, pp. 907-923
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).ASTM, C18, "C615-03 Standard Specification for Granite Dimension Stone", ASTM, 2007, pp. 49-50 ASTM, C18, "C503-05 Standard Specification for Marble Dimension Stone", ASTM, 2007, pp. 30-31 ASTM, C18, "C568-03 Standard Specification for Limestone Dimension Stone", ASTM, 2007, pp. 45-46
Production
The major producers of dimension stone include Brazil, China, India, Italy, and Spain, and each have annual production levels of nine to over twenty-two million tons. Portugal produces 3 million tons of dimension stone each year.World Rocks. World Rocks. Retrieved on 2014-04-12.
According to the USGS, 2007 U.S. dimension stone production was 1.39 million tons valued at $275 million, compared to 1.33 million tons (revised) valued at $265 million in 2006. Of these, granite production was 453,000 tons valued at $106 million in 2007 and 428,000 tons valued at $105 million in 2006, and limestone was 493,000 tons valued at $93.3 million in 2007 and 559,000 tons valued at $96.1 million in 2006. The United States is at best a mid-level dimension stone producer on the world scene; Portugal produces twice as much dimension stone annually.