Stone Dictionary E-H


– 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.

Entasis — the curve
of the upper two-thirds of a column.

Expansion 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 marble units designed to expand or contract with temperature
changes. An expansion joint compresses as panels expand.

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

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 faces; often used in combination with mouldings.


– F –

Ferriginous —
limestone or sandstone containing a high proportion of iron oxide.

Field stone — 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.

Filling — a trade
expression used in the fabrication of marble to indicate the filling of natural
voids with cements, shellac or synthetic resins and similar materials.

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

Finish — final
surface applied to the face of stone during fabrication.

Finished stone
— building stone with one or more mechanically dressed surfaces.

Fireproof — relatively
incombustible.

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.

Fleuri cut — cutting
quarried marble or stone parallel to the natural bedding plane.

Flooring — stone
used as an interior pedestrian wearing surface.

Fracture — a break
in rock produced by mechanical failure. Fractures include faults and joints.

Freestone — a stone
that may be cut freely in any direction without fracture or splitting.


– 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 intergrowths 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.