Stone Dictionary A – D

– A –

Abrasive finish
— a flat non-reflective surface finish for marble.

Abutment — a solid
stone springer at the lowest point of an arch or vault.

Adhered — veneer
secured and supported through adhesion to an approved bonding material applied over
an approved backing.

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 the and dowel and wire toggle bolt.

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

Architrave — the
member of an entablature resting on the capitals of columns and supporting the frieze.

Argillite — a compact
sedimentary rock composed mainly of clay and aluminium silicate minerals.

Arkose — a sandstone
containing 10 per cent or more clastic grains of feldspar. Also called arkosic sandstone,
feldspathick sandstone.

Arris — a natural
or applied line on the stone from which all levelling and plumbing is measured.

Ahslar — masonry
having a face of square or rectangular stones, either smooth or textured.

– B –

Back arch —
a concealed arch carrying the backing of a wall where the exterior facing is carried
by lintel.

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

Bed — the top or
bottom of a joint, natural bed; surface or stone parallel to its stratification.

Bed — In granites
and marbles, a layer or sheet of the rock mass that is horizontal, commonly curved
and lenticular, as developed by fractures. Sometime applied also to the surface
of parting between sheets.

Bed (1) — In stratified
rocks the unit layer formed by sedimentation; of variable thickness, and commonly
titled or distorted by subsequent deformation; generally develops a rock cleavage;
parting, or jointing along the planes of stratification.

Belt course — a
continuous horizontal course of flat stones placed in line marking a division in
the wall plane.

Bevel — when the
angle between two sides is greater or less than a right angle.

Bluestone — a dense,
hard, fine-grained, commonly feldspatic sandstone or siltstone of medium to dark
or bluish-grey colour 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 flagstones, the thin relatively smooth-surfaced slabs being suitable
for use as flagging. The term has been applied particularly to sandstone 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 schist 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.

Bond stone — used
in varying percentages to anchor or bond the stone veneer to the backing material.
Bond stones are generally cut to twice the bed thickness of the material being used.

Border stone
usually a flat stone used as an edging material. A border stone is generally used
to retain the field of the terrace of 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 — sandstone
of characteristic brown or reddish-brown colour 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.

Bull nose — 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. Some calcarenite
contain oolites (small, spherical grains of calcium carbonate that resemble roe)
and may be termed oolite limestone. Calcareous sandstone, in which the calcium carbonate
is present chiefly as bonding material, are not included in this category.

Calcite limestone
— a limestone containing not more than five per cent of magnesium carbonate.

Calcite streaks
— description of a white or milky-like streak occurring in stone. It is a joint
plane usually wider than a glass seam and has been re-cemented by deposition of
calcite in the crack and is structurally sound.

Canopy — a sheltering
roof, as over a niche or a doorway.

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.

Caulking — making
a marble joint tight or leak-proof by sealing with an elastic adhesive compound.

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

Cement putty
a thick, creamy mixture made with pure cement and water which is used to strengthen
the bond between the store and the setting bed, also called cement butter cement

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 de-laminate.

Coating — a protective
or decorative converting applied to the surface or impregnated into stone for such
purposes as waterproofing enhancing resistance to weathering, wear, and chemical
action, or improving appearance of the stone.

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

Commercial marble
— a crystalline rock composed predominantly of calcite dolomite and/or serpentine,
and capable of taking a polish.

Composite — a construction
unit in which stone that is to be exposed in the final use is permanently bonded
or joined to other material, which may be stone or manufactured material, that will
be concealed.

Contraction joint
— spaces where panels are joined and which expand as the panels contract.

Control joint
provision for the dimensional change of different parts of a structure due to shrinkage,
expansion, temperature variation or other causes so as to avoid the development
of high stresses.

Coping — a flat
stone used as a cap on freestanding walls.

Coquina —limestone
composed predominantly of unaltered shells or fragments of shells loosely cemented
by calcite, generally very coarse-textured with a high porosity. The term has been
applied principally to a very porous shell rock of Eocene age that has been quarried
in Florida.

Corbel plates
plates of non-ferrous metal fixed into a structure to support stone cladding at
intervals and over opening in such a way as not to be visible.

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 moulded
projecting stone at the top of an entablature.

Course — a horizontal
range of stone units the length of the wall.

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

Crack — a break,
split, fracture, fissure, separation, cleavage or elongated narrow opening, however
caused, visible without magnification to the human eye and extending from the surface
into the stone, that must extend through the grain or matrix.

Cross bedding
the arrangement of laminations of strata transverse or oblique to the main planes
of stratification.

Crowfoot (styoite)
— description of a dark grey to black zigzag marking occurring in stone. Usually
structurally sound.

Crystalline limestone
— a limestone, either calcitic or dolomitic, composed of interlocking crystalline
grains of the constituent minerals and of phaneritic texture; commonly used synonymously
with marble an thus representing a re-crystallised limestone; improperly applied
to limestone that display some obviously crystalline grains in a fine-grained mass
but which are not of interlocking texture and do not compose the entire mass. Note:
All limestone are microscopically, or in part megascopically, crystalline; the term
is thus confusing but should be restricted to stones that are completely crystalline
and of megascopic and interlocking texture and that may be classed as marbles.)

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 tread, risers, copings, borders, sills, stools, hearths, mantels,
and other special purpose stones.

– D –

Dacite —
a fine-grained, extrusive (volcanic) rock, intermediate in colour and composition
between basalt and rhyolite.

Damp proofing
one or more coating of a compound that is impervious to water applied to a surface
above grade.

Defect — those
features, which affect or have the potential of affecting the structural soundness
of building stone, or may affect the durability of the building stone. Sometimes
used for visual features such as xenoliths or veins.

Dentil — Blocks
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.

Dentil — small,
rectangular blocks under a classical cornice, resembling a row of teeth.

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

Dolomitic limestone
— a limestone rich in magnesium carbonate, frequently somewhat crystalline in character,
found in ledge formations in a wide variety of colour tones and textures. Generally
speaking, its crushing and tensile strengths are greater than the oolitic limestone
and its appearance shows greater variety in texture.

Dowel — a short
piece of non-ferrous metal or slate fixed into a mortise or sinking in the joints
of adjoining stones to prevent movement.

Dressed or handed-dressed
— the cutting of rough chunks of stone by hand to create a square or rectangular
shape. A stone that is sold as dressed stone generally refers to stone ready for
installation. Sometimes called scabbling.

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.

Dripstone — a projecting
moulding over the heads of doorways, windows and archways to throw off the rain.
Also known as a “hoodmould” and, when rectangular, as a “label”.

Dry — an open or
unhealed joint plane not filled with calcite and not structurally sound.

Dry 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.

Durability — the
measure of the ability of natural building stone to endure and to maintain its essential
and distinctive characteristics of strength, resistance to decay, and appearance,
with relation to a specific manner, purpose, and environment of use.