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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.
Glass seam : description of a narrow glass-like streak occurring in stone; a joint plane that has been re-cemented by deposition of translucent calcite in the crack and structurally sound.
Grade course : beginning course at the grade level, generally waterproofed with a damp check or damp course.
Grain : the easiest cleavage direction in a stone. "With the grain" same as "natural bed." Also, particles (crystals, sand grains, etc.) of 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 included those of similar texture and origin.
Granite (scientific definition) : a visibly granular, crystalline rock of predominantly interlocking texture, composed essentially of alkalic feldspars and quartz; this is true granite. Feldspar is generally present in excess of quartz, and accessory minerals (chiefly micas, hornblende, or more rarely pyroxene) are commonly present. The alkalic feldspars may be present (1) as individual mineral species (2) as isomorphous or mechanical intergrowths with each other or (3) as chemical tergrowths with the lime feldspar molecule, but 80 + 3% of the feldspar must be composed of the potash or soda feldspar
molecules.
Granite (commercial/building use) : a term that includes granite (as defined above), gneiss, gneissic granite, granite gneiss, and the rock species known to petrologists as syenite, monzonite, and granodiorite, species intermediate between them, the gneissic varieties and gneisses of corresponding mineralogic compositions and the mineralogic compositions and the corresponding varieties of porphyritic textures. The term commercial granite shall also include other feldspatic crystalline rocks of similar textures, containing minor amounts of accessory minerals, used for special decorative purposes, and known to
petrologists as anorthosite and laurvikite.
Granite gneiss : a foliated crystalline rock composed essentially of silicate minerals with interlocking and visibly granular texture, and in which the foliation is due primarily to alternating layers, regular or irregular, of contrasting mineralogic composition. In general, gneiss is characterised by relatively thick layers as compared with schist. According to their mineralogic compositions, gneisses may correspond to other rocks of crystalline, visibly granular, interlocking texture, such as those included under the definition of commercial granite, and may then be known as granite gneiss if strongly foliated,
or gneissic granite if weakly foliated. • Black granite : rock species known to petrologists as diabase, diorite, gabbro, and intermediate varieties are sometimes
quarried as building stone, chiefly for ornamental use, and sold as "black granite". As dimension blocks of slabs, they are valued specifically for their dark grey to black colour when polished. Scientifically, they are far removed in composition form true granites though they may be satisfactorily used for some of the purposes to which commercial granite are adapted. They posses as interlocking crystalline texture, but unlike granite, they contain little or no quartz or alkalic feldspar, and are characterised by an abundance of one or more of the common black rock-forming minerals (chiefly pyroxenes, hornblende, and biotite).
Granular : having a texture characterised by particles that are apparent to the unaided eye. For sedimentary rocks: particles less than 4 inches (10mm) in diameter and approximately in size.
Greenstone : includes stone that have been metamorphosed or otherwise changed so that they have assumed a distinctive greenish colour owing to the presence of one or more of the following minerals: chlorite, epidote, or actinolite. Greenstone is an old field term applied to metamorphosed igneous rock of mafic or ultramafic (low silica) composition (i.e., basalt, diabase, gabbro, peridotite and serpentinite). • Greenstone derived from basalt and other dark volcanic rocks consists dominantly of epidote, actinolite and plagioclase. No
present commercial production such rocks is known. Peridotite consist dominantly of olivine and pyroxene.
• Serpentine consist largely of talc, chlorite, and serpentine; further alteration may result in soapstone.
Grout : mortar of pouring consistency. Coarse grout, used for wide grout spaces 2 inches (5cm) or more, consist of one part
Portland cement, not more than two to three parts sand, and not more than two parts pea gravel. Fine grout, used in narrow grout spaces, consist of one part Portland cement and two-and-one quarter to three parts sand.
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 鈥� a finish given to both veneer stone and cutting stock. Establishing a straight line back from the irregular face of the stone creates this. 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 that has been tooled to march the face of the stone. Heads are used at outside corners, windows, doorjambs, 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 of the fire chamber and many times extending on either or both sides of the front of the fire chamber.
Holes : sinkages in the top beds of stones to engage Lewis pins for hoisting.
Honed finish : honed is a super fine smooth finish, thought 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
Lava : a general term applied to igneous rocks, such as basalt and rhyolite, that erupted from the earth by volcanic action.
Lead buttons : lead spacers in the solid horizontal joints to support the top stones until the mortar has set.
Lewis holes : holes in cut stones for lifting and support during setting of cut stones and sometimes for permanent support. Holes are checked for the particular Lewis lifting device or hook to be used.
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% 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.
Liners : structurally sound sections of marble that are cemented to the back of marble veneer slabs to give greater strength, additional bearing surface, or to increase joint depth.
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 : literally, badlands; refers to dark-coloured rock, commonly lava, in rough terrain. As defined for architectural use: calcium carbonate with other components which give it colour, markings and texture suitable as a desirable building stone.
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, magnesium carbonate, magnesium or dolomite marble. These limiting values are, however, not strictly established in petrologic science and are used herein as arbitrary limits.• Onyx 鈥� so called in trade, is a crystalline form, commonly micro crystalline, 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 鈥� marble characterised by a prominent amount of the mineral serpentine. • Travertine 鈥� a form of limestone precipitated from ground waters as in caves or in orifices of springs (see limestone). • Verde antique 鈥� 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 adjective modifier Verde (or verd) antique. Verde antique is commonly veined with carbonate minerals, chiefly calcite and dolomite.
Masonry : built up construction , usually of a combination of materials set in mortar.
Metamorphism : the change or alteration in a rock cause by exterior agencies such as deep-seated heat and pressure, or intrusion or rock materials.
Miter : the junction of two units at an angle of which the junction lines usually bisect on a 450 angle.
Modular multiple-cut (pattern-cut) : this refers to standard pattern 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 ¼ - ½ inch (6 or 13mm) joints or beds.
Mouldings : decorative stone deviating from a plane surface by projections, curved profiles, recesses or any combination thereof.
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. This generally applies to all stratified materials.
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.
Non-Staining mortar : Mortar composed of materials which individually or collectively do not contain material that will stain, usually having a very low alkali content.
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.
Oolitic limestone : A calcite-cemented calcareous stone formed of shells and shell fragments, practically non-crystalline in character. It is found in massive deposits located almost entirely in Lawrence, Monroe, and Owen Counties, IN, and Alabama, Kansas, and Texas. This limestone is characteristically freestone, without cleavage planes, possessing a remarkable uniformity of composition, texture and structure, It possesses a high internal elasticity, adapting itself without damage to
extreme temperature changes.
Opalized : The introduction into a rock of siliceous material in the form of opal, hydrous silicate.
Out of wind : The be out of wind is to have the arris of the stone not in parallel or perpendicular lines. Stone that is out of wind has an irregular or rustic appearance.
P
Palletised : A system of stacking stone on wooden pallets. Stone, which comes palletised, is easily moved and transported by modern handling equipment. Palletised stone generally arrives at the job site in better condition than UN-palletised material.
Panel : A finished stone unit used on walls.
Parapet wall : That part of any wall entirely above the roofline.
Parging : Damp-proofing by placing a coast of ½ inch (13mm) setting mortar to the back of stones or the face of the back-up material.
Parquetry : An inlay of stone floors in stones or the face of back-up material.
Paving : Stone used as an exterior-wearing surface, as in patios, walkways, driveways, etc. (see flooring).
Perforated wall : One that contains a considerable number of relatively small openings, often called pierced wall or screen wall.
Perrons : Slabs of stone set on other stones serving as steps and arches in gardens.
Phenocryst : In igneous rocks, the relatively large and conspicuous crystals in a finer-grained matrix or ground mass.
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 used along the line that 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.
Pointing : The final filling and finishing of mortar joints that have been raked out.
Polished finish : The finest and smoothest finish available in stone characterised by a high lustre (gloss) and strong reflection of incident light, generally only possible on hard, dense materials.
Porphyry : An igneous rock in which relatively large and conspicuous crystal (Phenocryst) are set in a matrix of finer crystals.
Pressure relieving joint : An open horizontal joint below the supporting angle or hanger located at approximately every floor line and not over 15 feet (4.6m) apart horizontally and every 20 to 30 feet (6 to 9m) vertically to prevent the weight from being transmitted to the masonry below, These joints are to be caulked with a resilient non-staining material to prevent moisture penetration.
Processing : The work involved in transforming building stone from quarry blocks to cut or finished stone. This includes primary sawing into slabs, It may also include both hand and mechanical techniques such as sawing, drilling, grinding, honing, polishing and carving.
Projections : This refers to the pulling out of stones in a wall to give an effect of ruggedness. The amount each stone is pulled out can vary between ½ and 1-½ inches (1.3 to 3.8 cm). Stones are either pulled out at the same degree at both ends or sometimes one end is pulled out, leaving the other end flush with the majority of the veneer.
Pumice : An exceptionally cellular, glassy lava resembling a solid froth.
(article from inspectstone)
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