GLOSSARY OF STONE TERMS

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z

 

A

 

abrasive finish – a flat non-reflective surface finish for marble.

agate – a variegated variety of quartz showing colored bands or other markings (clouded, moss-like, etc.).

anchors – 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).

arch – a curved stone structure resting on supports at both extremities used to sustain weight, to bridge or roof an open space.

architrave – the member of an entablature resting on the capitals of columns and supporting the frieze.

armorstone – large quarrystone used primarily for riprap retaining walls. Dense limestone, buff to grey in color

arris – a natural or applied line on the stone from which all leveling and plumbing is measured.

ashlar – masonry having a face of square or rectangular stones, either smooth or textured.

 

B

 

baluster – a miniature pillar or column supporting a rail, used in balustrades.

basalt – a dense-textured (aphanitic), igneous rock relatively high in iron and magnesia minerals and relatively low in silica, generally dark grey to black, and feldspathic; a general term in contradistinction to felsite, a light-colored feldspathic and highly siliceous rock of similar texture and origin.

bed – (1) In granites and marbles, a layer or sheet of the rock mass that is horizontal, commonly curved and lenticular, as developed by fractures. Sometimes applied also to the surface of parting between sheets. (2) In stratified rocks the unit layer formed by semidentation; of variable thickness, and commonly tilted or distorted by subsequent deformation; generally develops a rock cleavage, parting, or jointing along the planes of stratification. (3)

bevel – when the angle between two sides is greater or less than a right angle.

bluestone – a dense, hard, fine-grained, commonly feldspathic sandstone or siltstone of medium to dark or bluish-grey color that splits readily along original bedding planes to form thin slabs. Bluestone is not a technical geologic term. It is considered to be a variety of flagstone, the thin relatively smooth-surfaced slabs being suitable for use as flagging. The term has been applied particularly to sandstones of Devonian age that are being or have been quarried in eastern New York and Pennsylvania and in western New Jersey, but similar stones that occur elsewhere may be included. It has also been applied in places to thinly-layered gneisses and schists that can be split and used as flagging, but such stones are not properly embraced by this definition, although they may be marketed properly as flagstone.

border stone – usually a flat stone used as an edging material. A border stone is generally used to retain the field of the terrace or platform.

box – a tapered metal box wedged in the top of columns or other heavy stones for hoisting.

broach – to drill or cut out material left between closely spaced drill holes; a mason’s sharp-pointed chisel for dressing stone; an inclined piece of masonry filling the triangular space between the base of an octagonal spire and the top of a square tower; a type of chisel used for working narrow surfaces.

brownstone – a sandstone of characteristic brown or reddish-brown color that is due to a prominent amount of iron oxide, as interstitial material.

brushed finish – Obtained by brushing the stone with a coarse rotary-type wire brush.

building stone, natural – rock material in its natural state of composition and aggregation as it exists in the quarry and is usable in construction as dimension building stone.

bullnose – convex rounding of a stone member, such as a stair tread.

 

C

 

calcarenite – limestone composed predominantly of clastic sand-size grains of calcite, or rarely aragonite, usually as fragments of shells or other skeletal structures

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

carve – shaping, by cutting a design to form the trade of a sculptor.

cashel – pulverized calcarenite used by the celts as plastic reinforcement before the advent of cement-based mortar

cavity vent – an opening in joints of masonry to allow the passage of air and moisture from the wall cavity to the exterior.

celtic – in the style of the masters Irish masons

celtic drystack – contruction of installation without the use cashel or mortar. Fitting is achieved though shaping

cement putty – a thick, creamy mixture made with pure cement and water which is used to strengthen the bond between the stone and the setting bed. Also called cement butter, cement cream.

chamfer – to bevel the junction of an exterior angle.

chat-sawn finish – a rough gangsaw finish produced by sawing with coarse chat.

cladding – non-loadbearing stone used as the facing material in wall construction that contains other materials.

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.

cobblestone – a natural rounded stone, large enough for use in paving; commonly used to describe paving blocks, usually granite, generally cut to rectangular shapes.

colonial drystack – stone fitting style employed by the American colonists to construct boundaries and livestock barriers as they cleared their field of stone on or in the top soil. Very little shaping is employed

coping – a flat stone used as a cap on freestanding walls.

corinthian – acommercial name for granite quarry in the Adirondack Mountains

cornerstone – a stone forming a part of a corner or angle in a wall. Also a stone laid at the formal inauguration of the erection of a building, not necessarily at a corner, usually incorporating a date or inscription.

cornice – a molded projecting stone at the top of an entablature.

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

cross-bedding – the arrangement of laminations of strata transverse or oblique to the main planes of stratification..

curbing – slabs and blocks of stone bordering streets, walks, etc.

cut stone – stone fabricated to specific dimensions.

cutting stock – a term used to describe slabs of varying size, finish, and thickness which are used in fabricating treads, risers, copings, borders, sills, stools, hearths, mantels, and other special purpose stones.

 

D

 

dentil – block projections on an entablature.

dentil course – the lower part of the cornice with dentils. The cornice is jointed to allow machine production of the dentils.

dentils – small, rectangular blocks under a classical cornice, resembling a row of teeth.

dimension stone – natural building stone that has been selected, trimmed or cut to specified or indicated shapes or sizes with or without one or more mechanically dressed surfaces.

dressed or hand-dressed – the cutting of rough chunks of stone by hand to create a square or rectangular shape.

drip – a recess cut under a sill or projecting stone to throw off water, preventing it from running down the face of the wall or other surface, such as a window or door.

drystack wall – a dry wall is a stone wall that is constructed one stone upon the other without the use of any mortar. Generally used for retaining walls.

 

E

 

efflorescence – a crystalline deposit appearing on stone surfaces typically caused by soluble salts carried through or onto the stone by moisture, which has sometimes been found to come from brick, tile, concrete blocks, cement, mortar, concrete, and similar materials in the wall or above.

entablature – in classical architecture, the upper part of an order, comprising architrave, frieze, and cornice.

exposed aggregate – phrase applied to the larger pieces of stone aggregate purposefully exposed for their color and texture in a cast slab.

 

F

 

face – this refers to the exposed portion of stone. The word “face” can also be used when referring to the edge treatment on various cutting stock materials.

fascia – a horizontal belt or vertical face; often used in combination with moldings.

fieldstone – loose blocks separated from ledges by natural processes and scattered through or upon the regolith (“soil”) cover; applied also to similar transported materials, such as glacial boulders and cobbles.

fines – the powder, dust, silt-size and sand-size material resulting from processing (usually crushing) rock.

flagstone – thin slabs of stone used for flagging or paving walks, driveways, patios, etc. It is generally fine-grained sandstone, bluestone, quartzite or slate, but thin slabs of other stones may be used.

flaming –natural looking surface restored through application of oxygen/butane flame directly to moistened cut surface

flatwork – horizontal flagstone cladding usually applied as paving

fleuri cut – cutting quarried marble or stone parallel to the natural bedding plane

frieze – the part of a classical entablature between the architrave and the cornice, usually decorated with sculpture in low relief

 
 

G

 

gangsawed – description of the granular surface of stone resulting from gangsawing alone.

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

grain – the easiest cleavage direction in a stone. “With the grain” same as “natural bed.” Also, particles (crystals, sand grains, etc.) of a rock.

granite – a fine to coarse-grained, igneous rock formed by volcanic action consisting of quartz, feldspar, and mica, with accessory minerals. Granite-type rocks include those of similar texture and origin.

H

 

hand-cut random rectangular ashlar – a pattern where all the stone is hand cut into squares and rectangulars. Joints are fairly consistent. Similar to sawed-bed ashlar in appearance.

hand or machine pitch-faced (rock-faced) ashlar – a finish given to both veneer stone and cutting stock. This is created by establishing a straight line back from the irregular face of the stone. Proper tools are then used to cut along the line, leaving a straight arris and the intended rustic finish on the face.

head – the end of a stone which has been tooled to match the face of the stone. Heads are used at outside corners, windows, door jambs, or any place where the veneering will be visible from the side.

hearth – that part of the floor of a fireplace of stone on which the fire is laid.

hearth stone – originally the single large stone or stones used for the hearth, now most commonly used to describe the stone in front of the fire chamber and many times extending on either or both sides of the front of the fire chamber.

honed finish – honed is a super fine smooth finish, though not as fine as a polished finish.

 

I

 

igneous – one of the three great classes of rock (igneous, sedimentary and metamorphic), solidified from molten state, as granite and lavas.

incise – to cut inwardly or engrave, as in an inscription.

inscription – lettering cut in stone.

 

J

 

jack arch – one having horizontal or nearly horizontal upper and lower surfaces. Also called flat or straight arch.

joint – the space between stone units, usually filled with mortar.

jointing scheme – architects drawing detailing dimensions, location and configuration of marble units and joints as related to the structure.

jumper – in ashlar patterns, a piece of stone of higher rise than adjacent stones which is used to end a horizontal mortar joint at the point where it is set.

 

K

 

keystone – the last wedge-shaped stone placed in the crown of an arch regarded as binding the whole.

 

L

 

large quarrystone – stone too heavy for one man to free-lift alone

limestone – a sedimentary rock composed of calcium carbonate; includes many varieties. (See oolitic limestone, dolomitic limestone, crystalline limestone.) Limestones that contain not more than five per cent magnesium carbonate may be termed calcite limestone, as distinguished from those that contain between five and 40% magnesium carbonate (magnesium or dolomitic limestone), and from those that contain in excess of 40% as the mineral dolomite (dolostone, formerly known as the rock dolomite). Recrystallized limestones and compact, dense, relatively pure microcrystalline varieties that are capable of taking a polish are included in commercial marbles.

lintel – the block of stone spanning the top of an opening such as a doorway or window; sometimes called a head.

lipping – usually refers to flagging materials; caused when two pieces of material to be joined together are slightly warped or twisted causing one of more edges to be higher or lower than the adjoining material.

lug sill – a stone sill set into the jambs on each side of masonry opening.

 

M

 

machine finish – the generally recognized standard machine finish produced by the planers.

marble (scientific definition) – a metamorphic (recrystallized) limestone composed predominantly of crystalline grains of calcite or dolomite, or both, having interlocking or mosaic texture. Marble that contains less than 5% magnesium carbonate may be termed calcite marble; from 5 to 40% magnesium carbonate, magnesian or dolomitic marble; and more than 40%, dolomite marble. These limiting values are, however, not strictly established in petrologic science and are used herein as arbitrary limits.

-onyx – so called in trade, is a crystalline form, commonly microcrystalline, of calcium carbonate deposited usually from cold-water solutions. It is generally translucent and shows a characteristic layering. The term onyx marble is technically a misnomer, as true onyx is a variety of cryptocrystalline fibrous silica (chalcedony), and is closely related in form and origin to agate.

-serpentine – marble characterized by a prominent amount of the mineral serpentine.

-travertine – a form of limestone precipitated from ground waters, as in caves or in orifices of springs (see limestone).

-verde antique – a commercial marble composed chiefly of massive serpentine and capable of taking a high degree of polish. Verde antique is not a true marble in the scientific sense, but is commonly sold as a decorative commercial marble and requires the adjectival modifier verde (or verd) antique. Verde antique is commonly veined with carbonate minerals, chiefly calcite and dolomite.

metamorphism – the change or alteration in a rock caused by exterior agencies, such as deep-seated heat and pressure, or intrusion of rock materials.

modular multiple-cut (pattern-cut) – this refers to standard patterns used throughout the stone industry. These patterns are usually based on multiples of a given height. Stone that is multiple cut or pattern cut is pre-cut to allow typically for 1⁄4 – 1⁄2-inch (6 or 13 mm) joints or beds.

mortar – a plastic mixture of cement, lime, sand, and water used to bond masonry units.

mosaic – a veneering which is generally irregular with no definite pattern. Nearly all the stone used in a mosaic pattern is irregular in shape.

N

 

natural bed – the setting of the stone on the same plane as it was formed in the ground.

natural cleft – this generally pertains to stones which are formed in layers in the ground. When such stones are cleaved or separated along a natural seam the remaining surface is referred to as a natural cleft surface.

 

O

 

obsidian – a glassy phase of lava.

onyx marble – a dense, crystalline form of lime carbonate deposited usually from cold-water solutions. Generally translucent and showing a characteristic layering due to mode of accumulation.

out of wind – to be out of wind is to have the arris of the stone not in parallel or perpendicular lines. Stone which is out of wind has an irregular or rustic appearance.

overburden – layer of soil and loose stone existing above the bedrock

 

P

 

parapet wall – that part of any wall entirely above the roof line.

parging – damp-proofing by placing a coat of 1⁄2-inch (13 mm) setting mortar to the back of stones or the face of the back-up material.

parquetry – an inlay of stone floors in geometrical or other patterns.

paving – stone used as an exterior wearing surface, as in patios, walkways, driveways, etc. (see flooring).

perrons – slabs of stone set on other stones serving as steps and arches in gardens.

pilaster – an engaged pier of shallow depth. In classical architecture, it follows the height and width of related columns, with similar base and cap.

pitched stone – stone having arris clearly defined; face, however, is roughly cut with pitching chisel (hand set) used along the line which becomes the arris.

plinths – the lower square part of the base of a column. A square base or a lower block, as of a pedestal. The base block at the juncture or baseboard and trim around an opening.

plucked finish – obtained by rough-planing the surface of stone, breaking or plucking out small particles to give rough texture.

polished finish – the finest and smoothest finish available in stone characterized by a high luster (gloss) and strong reflection of incident light, generally only possible on hard, dense materials.

pure-blue bluestone – unweathered bluestone, homogeneous in color. Usually cut from sawrock, but can exist as natural flagging.

Q

 

quarry – the location of an operation where a natural deposit of stone is removed from the ground.

quarrystone – stone extracted from a quarry as opposed to fieldstone that has been harvested from the regolith (soil) surface

quartz – a silicon dioxide mineral that occurs in colorless and transparent or colored hexagonal crystals and also in crystalline masses. One of the most common minerals, the chief constituent of sandstone.

quartzite – a compact granular rock composed of quartz crystals, usually so firmly cemented as to make the mass homogenous. The stone is generally quarried in stratified layers, the surfaces of which are unusually smooth. Its crushing and tensile strengths are extremely high; the color range is wide.

quirt – a groove separating a bed or other molding from the adjoining members.

quoins – stones at the corner of a wall emphasized by size, projection, rustification, or by a different finish.

R

 

rampart – stone veneer with concrete or block core

range – a course of any thickness that is continued across the entire face. All range courses need not be of the same thickness.

regolith – dry surface coving of the earth

relief or relieve – ornament in relief. The ornament or figure can be slightly, half, or greatly projected.

relieving arch – one built over a lintel, flat arch or smaller arch to divert loads, thus relieving the lower member from excessive loading. Also known as discharging or safety arch.

return – the right angle turn of a molding.

return head – stone facing with the finish appearing on both the face and the edge of the same stone, as on the corner of a building.

reveal – the depth of stone between its outer face and a window or door set in an opening.

ribbon – narrow bands of rock differing to various degrees in chemical composition and color from the main body of the slate or stone; in other words, bands.

rift – the most pronounced (see “grain”) 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.

rip rap – irregularly shaped stones used for facing bridge abutments and fills; stones thrown together without order to form a foundation or sustaining walls.

rise – the heights of stones, generally used in reference to veneer stone.

riser – vertical face of a step

rock – an integral part of the earth’s crust composed of an aggregate of grains of one or more minerals. (Stone is the commercial term applied to quarry products.)

rock (pitch) face – similar to split face, 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.

Roman arch – semi-circular arch.

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

running bond – unduly continuous line of juncture between the edges of stacked or fitted stones detrimental to the integrity (mechanically or aesthetically) of  a structure

rustication – chamfers or square sinkings round the face edges of individual stones to create shadows and to give an appearance of greater weight to the lower part of the building. When only the horizontal joints are sunk, the device is known as banded rustication.

S

sandstone – a sedimentary rock consisting usually of quartz, cemented with silica, iron oxide or calcium carbonate. Sandstone is durable, has a very high crushing and tensile strength and a wide range of colors and textures. Varieties of sandstone are commonly designated by the kind and prominence of interstitial and bonding materials, as siliceous sandstone (bonding material primarily silica), calcareous sandstone (calcium carbonate prominent as bonding material or as accessory grains or both), argillaceous sandstone (clay minerals prominent as interstitial or bonding materials, or as thin laminac), ferruginous sandstone (iron oxide or hydroxide minerals [hematic, limonite, et al] as interstitial or as bonding materials in sufficient amount to impart appreciable color to the stone); brownstone (ferruginous sandstone of dark brown or reddish brown color), arkose, arkosic sandstone, or feldspathic sandstone (a sandstone that contains an abundance of grains of feldspar), conglomerate (a sandstone composed in large part of rounded pebbles, also called puddingstone). The term “brownstone” was applied originally to certain Trassic sandstones of the Connecticut Valley in Massachusetts (Longmeadow sandstone), Connecticut (Portland sandstone), and to similarly appearing reddish-brown sandstone quarried in and near Hummelstown, PA. Thus the term originally had geographic significance, but such geographic limitation is undesirable.

sawed edge – a clean cut edge generally achieved by cutting with a diamond blade, gangsaw or wire saw.

sawed face – a finish obtained from the process used in producing building stone; varies in texture from smooth to rough and coincident with the type of materials used in sawing; characterized as diamond sawn, sand sawn, chat sawn and shot sawn.

sawrock – large monolithic blocks quarried from solid homogenous mineral deposits unmarked by and void of any weathering. Color is consistent throughout the block

scale – thin lamina or paper-like sheets of rock, often loose, and interrupting an otherwise smooth surface on the stone.

schist – a loose term applying to foliated metamorphic (recrystallized) rock characterized by thin foliae that are composed predominantly of minerals of thin platy or prismatic habits and whose long dimensions are oriented in appoximately parallel positions along the planes of foliation. Because of this foliated structure, schists split readily along these planes and so possess a pronounced rock cleavage. The more common schists are composed of the micas and other mica-like minerals (such as chlorite) and generally contain subordinate quartz and/or feldspar of comparatively fine-grained texture; all graduations exist between schist and gneiss (coarsely foliated feldspathic rocks).

scotia – a concave molding.

serpentine – a hydrous magnesium silicate of igneous origin, generally a very dark green color with markings of white, light green or black. One of the hardest varieties of natural building stone.

shaped stone – cut stone which has been carved, ground or otherwise processed.

sill – a flat stone used under windows, doors, and other masonry openings.

slab – a lengthwise cut of a large quarry block of stone produced by sawing or splitting in the first milling or quarrying operation. A slab has two parallel surfaces.

slate – a very fine-grained metamorphic rock derived from sedimentary rock shale. Characterized by an excellent parallel cleavage entirely independent of original bedding, by which cleavage the rock may be split easily into relatively thin slabs. Essential mineral constituents of slates are usually members of the mica group, commonly sericite, muscovite, and paragonite; of the clay group, chiefly illite and kaolinite; and of the chlorite group. Common accessory minerals are iron oxides, calcite, quartz, and feldspar. Other minerals may be present also as minor accessories. Most slates are derived from shales. Others are derived from fine-grained igneous rock, chiefly volcanic tuffs, but these are rare and of little commercial importance.

slip sill – a stone sill set between jambs (see lug sill).

smooth finish – description of the finish produced by planer machines plus the removal of objectionable tool marks. Also known as “smooth planer finish” and “smooth machine finish.”

snapped edge, quarry cut or broken edge – a natural breaking of a stone either by hand or machine. The break should be at right angles to the top and bottom surfaces.

soapstone – a massive variety of talc with a soapy or greasy feel used for hearths, washtubs, table tops, carved ornaments, chemical laboratory counters, etc., and known for its stain-proof qualities.

soffit – the finished, exposed underside of a lintel, arch or portico.

spalls – sizes may vary from chip-size to one- and two-man stones. Spalls are primarily used for taking up large voids in rough rubble or mosaic patterns.

spline – a thin strip of material, such as wood or metal, inserted into the edges of two stone pieces or stone tiles to make a butt joint between them.

stone – sometimes synonymous with rock, but more properly applied to individual blocks, masses or fragments taken from their original formation or considered for commercial use.

stool – a flat stone, generally polished, used as an interior sill.

stratification – a structure produced by deposition of sediments in beds or layers (strata), laminae, lenses, wedges, and other essentially tabular units.

the same material as e marble in which it occurs.

surround – an enframement.

T

 

tablet – a small, flat slab or surface of stone, especially one bearing or intended to bear an inscription, carving or the like.

template – a pattern for repetitive marking or fabricating operation.

terrazzo – a type of concrete in which chips or pieces of stone, usually marble, are mixed with cement and are ground to a flat surface, exposing the chips, which take a high polish.

thermal    natural appearing finish accomplished through flamingthin stone/thin veneer – a cladding under 2 inches (50 mm) thick.

tile – a thin modular stone unit.

tolerance – dimensional allowance made for the inability of men and machines to fabricate a product of exact dimensions.

tooled finish – customarily has four, six, or eight parallel, concave grooves to the inch.

travertine limestone – a variety of limestone that has a partly crystalline or microcrystalline texture and porous or cellular layered structure.

travertine marble – a variety of limestone regarded as a product of chemical precipitation from hot springs

tread – a flat stone used as the top walking surface on steps – horizontal surface of a step

trimmer arch – a stone arch, usually a low-rise arch, used for supporting a fireplace hearth.

U

 

undercut – cut so as to present an overhanging part.

V

vein cut – cutting quarried marble or stone perpendicular to the natural bedding plane.

veneer – a non-loadbearing facing of stone attached to a backing for the purpose of ornamentation, protection or insulation. Veneer shall support no vertical load other than its own weight and possibly the vertical dead load of veneer above.

verde antique – a marble composed chiefly of massive serpentine and capable of being polished. It is commonly crossed by veinlets of other minerals, chiefly carbonates of calcium and magnesium.

W

 

wash – a sloped area or the area water will run over.

waterwashed – stone that has been exposed to the abrasive effects of rushing aggregate-filled water for long periods of time causing a smoothing effect to the exposed surfaces

wear – the removal of material or impairment of surface finishing through friction or impact use.

weathering – natural alteration by either chemical or mechanical processes due to the action of constituents of the atmosphere, surface waters, soil and other ground waters, or to temperature change

wedging – splitting of stone by driving wedges into planes of weakness.

wire saw – method of cutting stone by passing a twisted, multi-strand wire over the stone and immersing the wire in a slurry of abrasive material.