Glossary of Stone Terms

 

 

abrasive hardness (Ha) A measure of the wearing qualities of stone for floors, stair treads, and other areas subjected to abrasion by foot traffic. Refer to ASTM C241.

absorption Percentage of moisture absorbed by weight. Refer to ASTM C97.

acid wash A treatment applied to the face of a stone to achieve a texture or finish that is distressed. Chemical treatments are more effective when applied to calcareous stones than to siliceous stone types. Recently, the use of acid and other types of chemical treatments has lessened due to environmental and disposal concerns. Chemical processes have been replaced by mechanical methods for the texturing of the stone face.

adhered Secured and supported by adhesion of an approved bonding material over an approved backing; is used in reference to stone veneer.

alkaline Pertains to a highly basic, as opposed to acidic, substance; for example, hydrogen or carbonate of sodium or potassium.

anchor A metal fastener used for securing dimension stone to a structure. Anchor types for stonework include those made of flat stock (strap, cramps, dovetails, dowel, strap and dowel, and two-way anchors) and round stock (rod cramp, rod anchor, eyebolt and dowel, flat-hood wall tie and dowel, dowel and wire toggle bolts).

anchorage The means by which slabs are attached to a self-supporting structure.

antique finish A finish that replicates rusticated or distressed textures. Produced through mechanical or chemical means to simulate the naturally occurring effects of the aging process.  apron A trim piece under a projecting stone top, stool, etc.

arch The curved or pointed construction over a doorway or opening. Arch shapes range from flat to semicircular or semielliptical to acutely pointed. 

ashlar A thin, dressed stone cut in square or rectangular shapes, typically used as a wall facing in a pattern of varying shapes and sizes. 

back-buttering The process of slathering the back of a stone tile with thinset material in order to ensure proper mortar coverage. This prevents hollow areas and subsequent future cracking of tiles. Also helpful to ensure a level installation.

base The bottom course of a stone wall, or the vertical first member above grade of a finished floor.

bearing check A slot cut into the back of dimension stone to allow entry of a supporting angle or clip.

bed 1. The top or bottom of a joint, natural bed; surface of stone parallel to its stratification. 2. In granites and marbles, a layer or sheet of the rock mass that is horizontal, commonly curved and lenticular, as developed by fractures. Sometimes also applied to the surface of parting between rock sheets. 3. In stratified rocks, the unit layer formed by sedimentation; of variable thickness, and commonly tilted or distorted by subsequent deformation. It generally develops a rock cleavage, parting, or jointing along the planes of stratification.

bed joint A horizontal joint between stones, usually filled with mortar, lead, or sealant.

belt course A continuous horizontal course, marking a division in the wall plane.

bevel A sloped surface contiguous with a vertical or horizontal surface.

bluestone A fine- to medium-grain, metamorphic, quartz-based stone of the U.S. Appalachian Plateau and other regions of the world. Formed in the Devonian Period, the upper stone is green and lilac in color, while the middle stone is dark gray and blue. 

bollard A free-standing stone post or guard.

bond 1. Overlapping of joints in successive courses. 2. To stick or adhere.

buttering Placing mortar on stone units with a trowel before setting them into position.

butt joint A method of joining two pieces by butting them together against each other. It is the simplest joint to make, but it is also the weakest unless reinforcement is used

canopy A sheltering roof, as over a niche or a doorway.

cap or capital The culminating stone at the top of a column or pilaster, often richly carved. 

cavity wall Masonry wall built with a continuous air space between the outer masonry, typically brick or stone, and the inner wall, typically concrete block or frame construction. Water that penetrates the outer masonry in driving rain runs down through the cavity and is directed out at the bottom through weep holes. See weep holes.

caulking Closing a joint by sealing with an elastic, adhesive compound.

cavity vent An opening in joints of stone veneer to allow the passage of air and moisture from inside the wall cavity to the exterior. The vents may be weep holes, plastic tubing, or wicks.

chamfer To cut away the edge where two surfaces meet in an external angle, leaving a bevel at the junction.

cladding An exterior veneer stone covering or siding.

cleavage The ability of a rock mass to break along natural surfaces; a surface of natural parting.

cleavage plane Plane or planes along which a stone may likely break or delaminate.

chiseled edge A process of mechanically chipping the tile edge, thus giving the stone a rustic, aged appearance.

 cleft finish Rough-surfaced stones such as slates that are cleaved or separated along a natural seam are referred to as natural cleft. These types of stones were formed as a result of metamorphic foliation.

cobblestone A dimension stone large enough for use in paving. A term commonly used to describe paving blocks, usually granite, and generally cut to rectangular shapes.

colonnade A range of columns supporting an entablature or one side of a roof.

column A vertical support, usually consisting of a base, shaft, and capital.

composite A construction unit in which stone that is to be exposed in the final use is permanently bonded or jointed to other material, which maybe stone or manufactured material, that will be concealed.

conglomerate A coarse-grained sedimentary rock, with clast grains larger than 2 mm.

control joint A joint that allows for dimensional changes of different parts of a structure due to shrinkage, expansion, variations in temperature, or other causes. Its purpose is to prevent development of high stresses in the structure.

coping A flat stone used as a cap on freestanding walls or swimming pools.

cornerstone A stone forming a part of a corner or angle in a wall.

cornice Any projecting ornamental molding that crowns or finishes the top of a building or wall.

course A horizontal range of stone units the length of a wall.

coursed veneer A veneer achieved by using stones of the same or approximately the same height. Horizontal joints run the entire length of the veneered area. Vertical joints are constantly broken, so that no two joints will be over one another.

cut stone Finished, dimensioned stone ready to set in place. 

damp proofing One or more coatings of a compound that is impervious to water. Usually applied to the back of stone or face of back of wall. 

diamond sawed Finish produced by sawing with diamond-toothed circular or gang saw.

dovetail slot A continuous groove with a trapezoid section resembling a dove’s tail. Used to hold support rods in the back of the stone element.

dowel A short piece of nonferrous metal or slate fixed into a mortice or sinking in the joints of adjoining stones to prevent movement.

drip A recess cut into the underside of projecting stone to divert and prevent water from running down the face of a wall or other surface of which it is a part.

efflorescence A salt deposit, usually in the form of a white powder residue, that forms on the surface of stone, brick, or mortar. It is caused by alkalies leached from the masonry and carried to the surface by moisture.

elevation A drawing of the vertical faces and elements of a structure, either interior or exterior.

epoxy resin A flexible, usually thermal setting resin made by the polymerization of an epoxide; used as an adhesive.

etched A decorative surface pattern created by a variety of methods, most often with abrasive chemicals or sandblasting.

expansion anchor or bolt A socket that grips a drilled hole in stone by expanding as the bolt is screwed into it.

expansion-contraction joint A joint between stone units designed to expand or contract with temperature change or structural movement.

exposed face The visible side of any stone element.  

fabricated Used in reference to dimension stone, it means manufactured and ready for installation.

face The exposed surface of stone on a structure.

fascia Any relatively narrow, flat, horizontal structural element, such as the part covering the joint between the top of a wall and the projecting eaves.

fieldstone Rough, irregularly shaped pieces of stone, used for various building applications such as freestanding walls, veneers, walkways, and hardscapes.

fines The powder, dust, silt-sized or sand-sized material resulting from processing, usually crushing, of stone.

finish Final surface applied to the face of dimension stone during fabrication.

fissure A hairline opening in the face of stone demonstrating stones natural characteristics; a lineal or non-directional void in the face and crystalline structure of stone that typically is very thin and irregular. See: Dry Seam.

flagstone Thin slabs of stone used for paving surfaces such as walks, driveways, and patios. They are generally fine-grained bluestone, other quartz-based stone, or slate, but thin slabs of other stones may also be used.

flamed finish See thermal finish.

fleuri cut To cut quarried marble or stone parallel to the natural bedding plane.

fluting Shallow, concave, parallel grooves running vertically on the shaft of a column, pilaster, or other surface.

frieze 1. A decorated band along the upper part of an interior wall. 2. The middle member of the entablature, located above the architrave and below the cornice.

gauged or gauging A grinding process to make all pieces of material to be used together the same thickness.

grain 1. The main direction of the mineral composition and arrangement in stone; it is also the easiest direction of cleavage. 2. A very small particle of rock, such as a sand grain.

granite A very hard, crystalline, igneous rock, gray to pink in color, composed of feldspar, quartz, and lesser amounts of dark ferromagnesian materials. Gneiss and black “granites” are similar to true granites in structure and texture, but are composed of different minerals. Commercial and scientific definitions of the granite group are explained in detail in ASTM C119.  grout Mortar used to fill joints.

guillotine cut Cutting a stone by the guillotine method offers a ragged, snapped and chipped edge. 

hand or machine pitch-faced (rock-faced) ashlar A rustic finish for veneer stone created by chiseling the stone face, usually with a hammer.

head The exposed surface of the jointed end of any given piece of stone with a gauged dimension not more than the minimum thickness of the material specified. Also known as “return head.”

hone finish A satin-smooth surface finish with little or no gloss, recommended for commercial floors. 

igneous Any of the various volcanic rocks, solidified after the molten state, such as granite.

impregnation Applying a chemical containing stain inhibitors that penetrates below the surface of the stone.

incise To cut inwardly or engrave, as in an inscription. 

joint A space between installed stone units or between a dimension stone and the adjoining material.

jointing scheme Architectural drawing detailing dimensions, location, and configuration of stone units and joints as related to structure.  

kerf A slot cut into the edge of a stone with a saw blade for insertion of anchors.

keystone The central stone of an arch, sometimes sculpted or otherwise embellished. 

lamination The gluing of two pieces of stone together to produce an edge that can be shaped to create an aesthetic appearance for countertops.

ledgestone Thin strips of stone, similar to ashlar cut, with exposed grain.

lewis bolt A bolt with a large, tapered head, fixed into stone or masonry, and sometimes used as a permanent support. 

lewis pin A pin (3/8" or 1/2") usually with an eye at the upper end. It is used in pairs to lift cubic stones for installation.

limestone A sedimentary rock composed primarily of calcite or dolomite. The varieties of limestone used as dimension stone are usually well consolidated and exhibit a minimum of graining or bedding direction. See definition of limestone group in ASTM C119.

liners Structurally sound sections of stone cemented and doweled to the back of thin stone units to give greater strength, additional bearing surface, or to increase joint depth.

lintel A horizontal beam or stone over the opening of a door or window that carries the weight of the wall above it.

lippage A condition where one edge of a stone is higher than adjacent edges, giving the finished surface an uneven appearance.  

marble A metamorphic crystalline rock composed predominantly of crystalline grains of calcite, dolomite, or serpentine, and capable of taking a polish. Commercial and scientific definitions of the marble group are explained in detail in ASTM C119.

metamorphic rock Rock altered in appearance, density, crystalline structure, and in some cases, mineral composition, by high temperature or intense pressure, or both. Includes slate derived from shale, quartz-based stone from quartzitic sand, and true marble from limestone.

miter The junction of two units at an angle. The junction line usually bisects on a 45° angle.

modular multiple-cut Also called patterncut, refers to standard patterns used throughout the stone industry that are usually based on multiples of a given height. Stone that is multiple-cut or pattern-cut is precut to allow typically for 1/4" to 1/2" joints or beds.

moldings Decorative stone deviating from a plane surface by projections, curved profiles, recesses or any combination thereof.

mosaic A veneering that is generally irregular, with no definite pattern. Nearly all stone used in a mosaic pattern is irregular in shape.

mullion A vertical member that divides a window or other opening into two or more panes. Sometimes, it is only an ornamental overlay.

natural stone A product of nature. A stone such as granite, marble, limestone, slate, travertine, or sandstone that is formed by nature, and is not artificial or man-made.

niche A recess in an interior or exterior wall usually for a statue or an urn, and typically semicircular in design.

nonstaining mortar Mortar composed of materials which individually or collectively do not contain material that will stain, usually having a very low alkali content.

notch A V-shaped cut made on the edge or head of a stone. 

off fall A remnant, or extra piece, from a partially cut slab. Off falls are often used for samples or additional projects.

ogee A stone molding with a reverse curved edge: concave above, convex below.  

palletizing A system of stacking stone on wooden pallets. Stone delivered palletized is easily moved and transported by modern handling equipment. It generally arrives at the job site in better condition than unpalletized material.

panel A single unit of fabricated stone veneer.

parging Applying a coat of mortar to the back of stone units, or to the face of the backup material.

parapet 1. a low wall to protect the edge of a terrace, roof, or balcony. 2. The portion of wall above the roof of a building.

patina When the surface of a material has changed in color or texture due to age or exposure to various elements, it is referred to as patina.

paver A single unit of fabricated stone for use as an exterior paving material.

paving Stone used as a wearing surface, as in patios, walkways, driveways, etc.

pedestal In classical architecture, the support for a column or statue, consisting of a base, dado, and cap.

pediment The gable end of a roof in classical architecture. Located above a horizontal cornice member, it comprises the raking cornices and the tympanum. It is typically triangular, but can also be curved when applied as a decorative element over windows.

pergola Garden structure formed by two rows of posts or pillars with joists and open framing above, often covered by climbing plants and shading a walkway.

pilaster A shallow, engaged pier or column projecting from a wall, typically decorative.

pillowed A tile finish that features softly rounded edges, thus giving the tile a pillowed look.

pitched stone A rough stone face or edge, cut with a pitching chisel.

plinth The base block at the junction of the stone base and trim around a door or other opening. The bottom stone block of a column or pedestal.

pointing The final filling and finishing of mortar joints that have been raked out.

polished finish A glossy surface finish that brings out the full color and character of the stone.

porphyry An igneous rock characterized by distinct and contrasting sizes of coarse and fine-grained crystals. Used as a decorative building stone. 

portico A porch formed by a roof supported with columns, similar to a temple front.

quarry The location of an operation where a deposit of stone is extracted from the earth through an open pit or underground mine.

quartz A silicon dioxide mineral that occurs in colorless and transparent or colored hexagonal crystals or in crystalline masses. One of the hardest minerals that compose stones such as sandstone, granite, and quartzite.

quartz-based stone A stone that may be either sedimentary in formation (as in sandstone, or metamorphic, as in quartzite). Definitions of the classes of stone which form the quartz-based stone group are explained in ASTM C119.

quartzite A metamorphic quartz-based stone formed in exceedingly hard layers. In some deposits, intrusion of minerals during the formation process create unusual coloration.

quirk-miter Linear edge work for corner joints.

quirk-miter joint An external corner formed by two stone panels at an angle, with meeting edges mitered and with exposed portions finished.

quoin One of the decorative dressed stones or bricks used at the corner of a building. Quoins are usually laid so their faces are alternately large and small.

rabbet A groove cut into the surface along an edge so as to receive another piece similarly cut.  rake An angular cut on the face of a stone.

rebated kerf An additional cut that countersinks a kerf from the back edge of the kerf to the back edge of another piece of stone for the purpose of additional anchor clearance. It is not a gauged cut. If used for a bearing surface, it must be shimmed to allow for tolerance in the cut.

reglet A narrow, flat, recessed molding, or a kerf cut to receive flashing.

reinforcement A fabrication technique, often called “rodding,” that refers to the strengthening of unsound marble and limestone by cementing rods into grooves or channels cut into the back of the stone unit. Another method of reinforcement is the lamination of fiberglass to the back of tile units.

relief Carving or embossing raised above a background plane, as in a bas-relief.

reprise Inside corner of a stone member with a profile other than a flat plane. 

resin A chemical product, clear to translucent, used in some coating processes.

return The right-angle turn of a molding.

reveal The exposed portion of a stone between its outer face and a window or door set into an opening.

rift The most pronounced direction of splitting or cleavage of stone. Rift and grain may be obscure, as in some granites, but are important in both quarrying and processing stone.

rise The height of a stone, generally used in reference to veneer stone.

rock (pitch) faced Similar to split faced, except that the face of the stone is pitched to a given line and plane, producing a bold appearance rather than the comparatively straight face obtained in split face.

rodding See reinforcement.

rough sawn A surface finish resulting from the gang sawing process.

rubble A term applied to dimension stone used chiefly for walls and foundations, consisting of irregularly squared pieces, partly trimmed or squared, generally with one split or finished face, and selected and specified with a size range.

rustication Exterior masonry cut in large blocks with deeply chamfered joints. Surfaces can be smooth or rough-textured, and joints and faces can have various treatments. 

saddles See thresholds

sandblasted A matte-textured surface finish with no gloss, finished by application of a steady flow of sand and water under pressure.

sawed edge A clean-cut edge generally achieved by cutting with a diamond blade, gang saw, or wire saw.

sawed face A finish obtained from the process used in producing blocks, slabs, or other units of building stone. It varies in texture from smooth to rough, and is typically named for the type of material used in sawing, e.g. diamond sawn, sand sawn, chat sawn, and shot sawn.

scabbing See dressing.

schist The schists form a group of medium-grade metamorphic rocks, chiefly notable for the preponderance of lamellar minerals such as micas, chlorite, talc, hornblende, graphite, and others. Quartz often occurs in drawn-out grains to such an extent that a particular form called quartz schist is produced. By definition, schist contains more than 50% platy and elongated minerals, often finely interleaved with quartz and feldspar. Schist is often garnetiferous.

scotia A concave molding

sculpture The work of a sculptor cutting a three-dimensional form from a block of stone.  sealant An elastic adhesive compound used to seal stone veneer joints.  

sealing 1. To make a veneer joint watertight with an elastic adhesive compound. 2. Application of a treatment to retard staining.

sedimentary Rocks formed of sediments laid down in successive strata or layers. The materials of which they are formed are derived from preexisting rocks or the skeletal remains of sea creatures.

serpentine A hydrous magnesium silicate material; generally dark green in color with markings of white, light green, or black. Considered commercially as a marble because it can be polished. Definition of serpentine is given in ASTM C119 under the marble group.

setter An experienced journeyman who installs dimension stone.

setting The trade of installing dimension stone.

setting space The distance from the finished face of a stone unit to the face of the backup material.

shim A piece of plastic or other noncorrosive, nonstaining material used to hold joints to size.

shop drawing A detailed fabrication and installation drawing showing dimensions and methods of anchorage.

shop ticket Also referred to as a “cutting” or “cut” ticket, it is generally produced by the stone fabricator or shop for in-house use and reference. A shop ticket is produced for each differing piece of stone required for a project and is referenced to shop drawings, which are used for communicating intent with parties outside of the fabricating team or shop.

sill The bottom horizontal part of a window or opening in a structure.

simulated stone An artificial man-made product that resembles real natural stone.

slab A lengthwise-cut piece sawn or split from a quarry block prior to fabrication.

slate A very fine-grained metamorphic rock derived from sedimentary shale rock. Characterized by an excellent parallel cleavage, and entirely independent of original bedding, slate may be split easily into relatively thin slabs. See definition of slate in ASTM C119.

soapstone A massive talc with a “soapy” feel, used for hearths, tabletops, chemical resistant laboratory tops, stove facings, and cladding; known for its stainproof characteristics. Classified in ASTM C119 as part of the greenstone group.

soffit The underside of any architectural element, such as an arch, beam, lintel, or balcony.

soundness A property of stone used to describe relative freedom from cracks, faults, voids, and similar imperfections found in untreated stone. One of the characteristics encountered in fabrication. 

spall A chip or splinter separated from the main mass of a stone.

spandrel 1. The triangular area between an arch and a wall, or between two arches. Often decorated. 2. In modern high-rise construction, the blank wall panel between the top of one window and the bottom of the one above it. Can be made of stone, metal, or glass.

splay A beveled or slanted surface.

split Division of a rock by cleavage.

split-faced stone Stone on which the face has been broken to an approximate plane. 

spot or spotting The mortar applied to the back of dimension stone veneer to bridge the space between a stone panel and the backup wall. Used to plumb a wall.

stacked bond Stone that is cut to one dimension and installed with unbroken vertical and horizontal joints running the entire length and height of the veneered area.

sticking The butt edge repair of a broken piece of stone, now generally done with dowels, cements, or epoxies. The pieces are “stuck” together; thus “sticking.”

stool A flat unit of stone, often referred to as an interior windowsill.

template A pattern for a repetitive marking or fabricating operation.

terrazzo A flooring surface of marble or granite chips in a cementitious or resinous matrix, which is ground and finished after setting.

texture Surface quality of stone independent of color.

textured finish A rough surface finish.

thermal finish A surface treatment applied by intense heat flaming.

thin stone Dimension stone units less than 2" thick.

thin stone veneer Dimension stone units less than 2" thick used as an exterior or interior siding.

threshold A flat strip of stone projecting above the floor between the jambs of a door. Also known as a “saddle.”

tile A thin modular stone unit, generally less than ¾" thick.

tolerance Dimensional allowance in the fabrication process.

translucence The ability of many lighter-colored marbles to transmit light.

travertine A variety of limestone that is a precipitate from hot springs. Some varieties of travertine take a polish and are known commercially as marble. ASTM C119 classifies travertine in both the limestone and the marble groupings.

tread A flat stone used as the top walking surface on steps.

trim The framing or edging of openings and other features on the interior or exterior of a building, including baseboards, picture rails, cornices, and casings.

tumbled finish A weathered, aging finished created when the stone is tumbled with sand, pebbles, or steel bearings. 

unit A piece of fabricated cubic or thin dimension stone.

undercut Cut so as to present an overhanging part. 

vein A layer, seam, or narrow irregular body of mineral material different from the surrounding formation. 

vein cut A cut into quarried stone perpendicular to the natural bedding plane.

veneer An interior or exterior stone wall covering layer.

venting See cavity vent.  

wainscot An interior veneer of stone covering the lower portion of an interior wall.

wash The slope on the top of a stone unit intended to shed water.

water-jet finish A surface treatment performed by using water under extreme high pressure.

waxing The practice of filling minor surface imperfections such as voids or sand holes with melted shellac, cabinetmaker’s wax, or certain polyester compounds. In the dimension stone industry, it does not refer to the application of paste wax to make surfaces shinier.

weathering Natural alteration by either chemical or mechanical processes due to the action of constituents of the atmosphere, soil, surface waters, and other ground waters, or by temperature changes.

weep holes Openings for drainage in veneer joints or in the structural components supporting the veneer.

wyth The inner or outer part of a cavity wall.

Created with the help of the Marble Institute of America .