Natural Stone Definitions
B
Back Anchor
Any of a variety of anchors that extends from the back surface of a stone panel, as opposed to anchors that penetrate the edges of a stone panel.
Backer Rod
A flexible and compressible type of closed-cell foam polyethylene, butyl rubber, or open-cell or closed-cell polyurethane, rounded at the surface to contact sealant. The backer rod is positioned within the joint so as to maintain the appropriate depth and cross-sectional shape of the bead.
Back-parging
The process of slathering the back of an adhered stone unit with an adhesive material to reduce or eliminate voids in adhesive contact. Also used in travertine or with the application of damp proofing. Also referred to as “back-buttering.”
Backsplash
A vertical covering of the wall where a countertop surface meets the wall surface, designed to protect the wall from moisture. Backsplashes range from a few inches in height to full-height backsplashes that extend from the countertop surface to the underside of the upper cabinets.
Back-up Structure
A structural support wall erected behind stone or brick facing.
Baluster
A short post or vertical member in a series that supports a railing or coping forming a balustrade. Balusters are traditionally decorative forms that are turned on a lathe.
Balustrade
A railing system with top rail, balusters, and bottom rail.
Band Course
Banker
Bench of timber or stone (may be a single block) on which stone is worked.
Basalt
A dark-colored, igneous rock commercially known as granite when fabricated as dimension stone. The fine-grained and extrusive equivalent of gabbro.
Base
In masonry, the bottom course of a stone wall, or the vertical first member above grade or a finished floor.
Basic
In geology, one of four subdivisions used to classify igneous rocks based on silica content: acidic, intermediate, basic, and ultra-basic. Said of igneous rock containing relatively low silica content (approx. 45 to 50%).
Batted Work (British)
Hand-dressed stone surface scored top to bottom in narrow parallel strikes, using a batting tool. Strokes may be vertical (in which case the surface may be called tooled) or oblique, and may range from 8 to 10 per inch. Batting is also called “broad tooling,” “droving,” or “angle dunting.”
Bearing Check
A slot, generally not continuous, cut into the back or bed of dimension stone to allow entry of a supporting angle or clip.
Bed Joint
A horizontal joint between stones, usually filled with mortar or sealant.
Bed
- The top or bottom of a joint, natural bed; the surface of stone parallel to its stratification.
- In granites and marbles, a layer or sheet of the rock mass that is frequently horizontal, commonly curved and lenticular, as developed by fractures. Sometimes also applied to the surface of parting between rock sheets.
- 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.
Bedding Plane
Plane of sedimentary stone in the position of its original formation. This plane may be horizontal, coincident with mountain slopes, or random.
Bedrock
General term referring to the rock underlying other unconsolidated material, such as soil.
Belt Course
A continuous horizontal course, marking a division in the wall plane.
Bench
Steps formed in a quarry by removal of stone. Also, a long seat of cubic stone bevel. A term describing the intersection of two surfaces meeting at an angle other than 90 degrees.
Bevel
A sloping surface, when the angle between two sides is greater or less than a right angle.
Black Granite
Rock species known to petrologists as diabase, diorite, gabbro, and other varieties quarried as dimension stone. As dimension blocks or slabs, they are valued specifically for their dark gray to black color when polished. Scientifically, they are far removed in composition from true granites though they may be satisfactorily used for some of the purposes to which commercial granites are adapted. They possess an interlocking crystalline texture, but unlike granites, they contain little or no quartz or alkalic feldspar and are characterized by an abundance of one or more of the common black rock-forming minerals (chiefly pyroxenes, hornblende, and biotite).
Blade Dressing
A maintenance process required periodically to restore the optimum performance of diamond abrasive cutting tools. The process consists of cutting or grinding into a softer material that will abrade at the matrix and expose new diamond surfaces. The dressing is frequently done with manufactured dressing sticks, soft brick, and some abrasive sandstones.
Bleed
Staining caused by corrosive metals, oil-based putties, mastics, caulking, or sealing compounds.
Blending
The random positioning of adjacent veneer panels, floor slabs, or tiles, to prevent large regions of uniform color, contrasted by adjacent large regions of dissimilar uniform color.
Block
Bluestone
A fine to medium-grain, quartz-based stone of the U.S. Appalachian Plateau. The stone is well-known for relatively easy cleavage along generally flat planes, making it a common choice for naturally cleft products such as flagstone. The term “bluestone” may be used in other parts of the world to describe very dissimilar regional products.
Bollard
A free-standing stone post or guard.
Bond
- Pattern of joints in successive courses.
- To stick or adhere.
Book-match Pattern
A vein matching technique where opposite faces of adjacent slabs are exposed, producing a repeating mirror image of the veining trend of the material. Book-matched material is most commonly polished to allow the greatest visibility of the veining character of the stone.
Border Stone
Usually a flat stone used as an edging material. A border stone is generally used to retain or define the pattern around the field of paving.
Boss
In masonry, a roughly shaped stone set to project for carving in place. A carved ornamentation to conceal the jointing at the junction of ribs in a Gothic vault.
Boulder
Naturally rounded rock fragment larger than 256mm diameter. Used for crude walls and foundation, generally in mortar.
Bowing
A warping or curving of a stone unit.
Breccia
Rock characterized by course, angular fragments, either the result of crushing and recementing essentially in place or deposition of angular pieces that become consolidated. Numerous marbles owe their distinctive appearance to the brecciation caused by metamorphism. Italian for, “broken stones, rubble.”
Brecciated Marble
Any marble composed of angular fragments.
Bridge Crane
A hoisting system that consists of a hoist, normally using cables, which moves on a beam or bridge spanning an opening between two rails. The hoist moves laterally along the bridge and the bridge moves longitudinally along the rails, allowing the hoist to be over any position within the rectangle contained within the lengths of the two rails.
Bridge Polisher
A single spindle polishing machine that travels along a beam, or bridge, which travels atop two rails. Also known as a “gantry” polisher.
Bridge Saw
A saw that travels along a beam, or bridge, which travels atop two rails. These saws are typically powerful and fitted with large diameter blades. A rotating table is positioned below the saw, allowing for skew cuts, and the saw arbor typically rotates, allowing for angled cuts.
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 trade term applied to ferruginous dark brown and reddish-brown arkosic quartz-based stone extensively used for construction in the U.S. during the 19th century.
Brushed Finish
A brushed finish is generally made by means of coarse rotary-type wire brushes that take away the softest particles of the stone. The brushing is done by machine. Varying brush coarseness and levels of force can be applied to achieve the desired look. Brushed finishes are low to non-slip. Surface roughness can vary from smooth (1/64 – 1/16”) to very rough (>2”) depending on the process. Leathered and antiqued are special cases of a brushed finish.
BSI (Building Stone Institute)
A trade association of quarriers, fabricators, dealers, and others working with natural stone. Founded in 1919, sponsor of the Tucker Architectural Awards.
Bugged Finish
A smooth finish produced in limestone by grinding with power sanders.
Building Stone
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. Also used interchangeably with the term dimension stone.
Bullnose
Convex rounding of a stone edge, such as a stair tread or countertop.
Bush Hammered Finish
Bush Hammering generates uniformly distributed craters of different sizes over the surface of the stone. Bush hammering patterns are generally random. Colors often fade to create a soft and delicate look. The overall effect is a rustic look. The surface becomes low or non-slip. Bush hammered finishes come in a number of variations including fine, fine free-form, coarse, and coarse free-form. Surface roughness of the fine variations can be smooth (1/64 – 1/16”) to somewhat rough (1/16-1/4”), depending on the process. Surface roughness of the coarse variations can be somewhat rough (1/16-1/4”) to very rough (>2”), depending on the process. Bush hammered finishes can be produced by hand or machine, although the hand-made finish is considered to be more attractive.
Butt Joint
A butt joint is a technique in which two pieces of material are joined by simply placing their ends together without any special shaping. The name ‘butt joint’ comes from the way the material is joined together. The butt joint is the simplest joint to make since it merely involves cutting the materials to the appropriate length and butting them together.
Buttering
Placing mortar on stone units with a trowel before setting them into position.
