Home > Search > Site Map > Quarries -
Economics, Methods, Stone Types... > Glossary of Scientific
and Quarry Terms
Glossary of Scientific and Quarry Terms
The following terms are quoted from The Chief Commercial
Granites of Massachusetts, New Hampshire and Rhode Island, Bulletin
354 (1908) and The Commercial Granites of New England,
Bulletin 738, both by T. Nelson Dale.
| Accessory Minerals |
Accessory minerals in granite are original constituents of
the rock, found only in small, often only in microscopic
quantity. |
| Acidic |
A term applied to rocks in which silicic acid (silica) or
quartz predominates. |
| Allanite |
An opaque black mineral (silicate), brown in thin section,
one of the primary less common accessory constituents of
granite, which contains from 12 to 17 elements, including
6 of the rarer ones. |
| Anticline |
A term applied to granite sheets or sedimentary beds that
form an arch. |
| Aplite |
Fine-grained granite, usually occurring in dikes and
containing little mica and a high percentage of
silica. |
| Basic |
A term applied to rocks in which the iron-magnesia
minerals and feldspars with lime and soda predominate,
such as diabase or basalts. |
| Black Horse |
Term used by quarrymen in Rhode Island to denote a dark
biotite gneiss in contact with the granite. |
| Blind Seams |
Quarrymen's term for incipient joints. |
| Bowlder Quarry |
One in which the joints are either so close or so
irregular that no very large blocks of stone can be
quarried. |
| Channel |
A narrow artificial incision across a mass of rock, which,
in the case of a granite sheet, is made either by a series
of contiguous drill holes or by blasting a series of holes
arranged in zigzag order. |
| Cleavage |
Cleavage, when applied to a mineral, designates a
structure consequent upon the geometrical arrangement of
its molecules at the time of its crystallization. |
| Close Jointed |
A term applied to joints that are very near
together. |
| Crocus |
A term used in the Milford, N. H., quarries to denote
gneiss or any other rock in contact with granite. |
| Crush-Border |
A microscopic granular structure sometimes characterizing
adjacent feldspar particles in granite in consequence of
their having been crushed together during or subsequent to
their crystallization. |
| Cut-off |
Quarrymen's term for the direction along which the granite
must be channeled, because it will not split. Same as
"hardway." |
| Dendrites |
Plantlike crystallization of iron or manganese oxides on
the surfaces of fissures in any rock or mineral. Frost
crystals on window panes are of like character. |
| Dike |
A mass of granite, diabase, basalt, or other rock which
has been erupted through a narrow fissure. |
| Dimension Stone |
A term applied to stones that are quarried of required
dimensions. |
| Dip |
The inclination from the horizon, given in terms of
degrees, of a sheet, joint, heading, dike, or other
structural plane in a rock. |
| Drift |
Sand and bowlders deposited by the continental
glacier. |
| Drumlin |
Oval hillock of clay and bowlders formed beneath the ice
sheet of the glacial epoch. |
| Erosion |
The wearing away of portions of a rock by such natural
agencies as stream or ice action. |
| Exfoliation |
The peeling of a rock surface in sheets owing to changes
of temperature or other causes. |
| Faulting |
The slippage of a rock mass or masses along a natural
fracture. |
| Flow-Structure |
The parallel arrangement of the minerals in granite or
other igneous rock in the direction of its flowage during
its intrusion. |
| Geode |
A rock cavity lined with crystals. Geodes in granite are
attributed to steam or gas bubbles. |
| Grain |
Grain in granite is practically the direction in which the
stone splits "next easiest," the "rift" being that in
which it splits most readily. |
| Grout |
A term applied to the waste material of all sizes obtained
in quarrying stone. |
| Grow-on |
Quarrymen's term to designate the place where the sheet
structure dies out, or the place where two sheets appear
to grow onto one another. |
| Hard-way |
The direction at right angles to both rift and grain in
which granite does not split readily. (See Cut-off.) |
| Heading |
A collection of close joints. |
| Heading-seam |
See Joint. |
| Hematite |
An oxide of iron.which when scratched or powdered gives a
cherry-red color. |
| Igneous |
A term applied to rocks that have originated in a molten
condition. |
| Joints |
More or less steeply inclined fractures which cross the
granite sheets and which are attributed to various
stresses. |
| Kaolin |
A hydrous silicate of alumina derived from the alteration
of feldspar. |
| Kaolinization |
The process by which a feldspar passes into kaolin. |
| Knots |
A term applied by quarrymen to dark gray or black objects,
more or less oval or circular in cross-section, which are
segregations of black mica or hornblende formed in the
granite while in a molten state. English quarrymen call
them "heathen." |
| Knox Hole |
A circular drill with two opposite vertical grooves which
direct the explosive power of the blast. |
| Lewis Hole |
An opening made by drilling two or three holes near
together and chiseling out the intervening rock. |
| Limonite |
A hydrous oxide of iron.;a hydrated hematite, which, when
scratched or powdered, gives a brownish rust color. |
| Matrix |
The general mass of a rock which has isolated crystals;
sometimes called groundmass. |
| Metamorphism |
The process, partly physical, partly chemical, by which a
rock is altered in the molecular structure of its
constituent minerals and in their arrangement.
Metamorphism may be regional, due to crustal compression,
or contact, due to the intrusion of sedimentary rock by an
igneous rock. |
| Millimeter |
French decimal lineal measure, the thousandth part of a
meter or the tenth part of a centimeter. It is equivalent
to nearly 0.04 inches, the meter being 10/27 inches. |
| Monolith |
A column or monument of one stone. |
| Motion |
A term used in granite regions to designate small
paving-block quarries. |
| Ophitic |
A term applied to microscopic rock texture to designate a
mass of longish interlacing crystals, the spaces between
which have been filled with minerals of later
crystallization. |
| Oreď |
A term applied to microscopic rock texture to designate a
mass of longish interlacing crystals, the spaces between
which have been filled with minerals of later
crystallization. |
| Pegmatite |
A very coarse granite occurring in irregular dikes or
lenses in granites and some other rocks. |
| Phenocryst |
A term applied to isolated crystals visible to the unaided
eye and lying in the mass of a rock of igneous
origin. |
| Plagioclase |
A term applied to all those feldspars that are not potash
feldspars. |
| Plug and Feathers |
A quarrymen's term. The plug is a wedge, and the feathers
are two short pieces of half-round iron whose curved sides
fit the drill hole while their flat sides receive the
plug. By driving the plugs in a series of holes a stone
may be broken. |
| Polarized Light |
Light whose vibrations, unlike those of ordinary light,
which are in all directions, are in only one plane.
Polarized light is used in the microscopic study of
rocks. |
| Porphyritic |
A term applied to rock texture to designate the presence
of isolated crystals in a general mass (matrix or
groundmass) of finer material. |
| Pseudomorph |
Signifies false form, and designates a crystal in which,
owing to various chemical changes, the original mineral
has been more or less replaced by others. The form of the
crystal no longer corresponds to the mineral. |
| Quartz Monzonite |
Technical designation for a granite in which the
percentages of soda-lime and of potash feldspar are nearly
the same or in which the former exceeds the latter. In
ordinary granites the amount of soda-lime feldspar is
relatively small. |
| Random Stone |
A term applied by quarrymen to quarried block of any
dimensions. (See definition of dimension stone.) |
| Rift |
A quarrymen's term to designate an obscure microscopic
cleavage in granite which greatly facilitates
quarrying. |
| Run |
A term used by quarrymen in connection with "rift,"
apparently to denote the course of the deflection of the
rift due to gravity, strain, or other not yet understood
cause. |
| Salt-Horse |
Quarrymen's term for aplite. |
| Sand Seams |
Quarry term for more or less minute veins or dikes of
muscovite (white mica) with some quartz, in cases also
with feldspar. |
| Sand Streaks |
Same as sand seams. |
| Sap |
Quarrymen's term for ferruginous discoloration along sheet
or joint surface. |
| Schist |
A rock made up of flattish particles arranged in rough
parallelism, some or all of which have crystallized under
pressure. |
| Schistosity |
The quality of being like a schist. |
| Seam |
Quarrymen's term for joint. |
| Secondary Minerals |
Minerals whose presence is due to the alteration of the
original minerals. |
| Sedimentary |
A term designating those rocks that consist of particles
deposited under water. |
| Segregation |
The scientific term for "knot;" a collection of material
separated from other material. A vein of segregation is
one formed by the filling of a fissure with mineral matter
originating in the surrounding rock. |
| Sericite |
A more or less fibrous form of muscovite (potash mica),
often resulting from the alternation of feldspar. |
| Shakes |
Quarrymen's term to designate a somewhat minute
close-joint structure, which forms along the sheet
structure as a result of weathering. |
| Sheet Quarry |
A quarry in which the granite lies in sheets, crossed by
wide-spaced steep joints. |
| Slickensides |
The polished and grooved faces of a joint or bed caused by
motion and friction. |
| Specific Gravity |
The weight of a rock or mineral compared to that of a body
of distilled water of the same bulk. |
| Strain-sheet |
The weight of a rock or mineral compared to that of a body
of distilled water of the same bulk. |
| Stratifield |
A term applied to rock consisting of originally horizontal
beds or strata. |
| Strike |
The direction at right angles to the inclination of a
plane of bedding, a sheet, or joint, etc. |
| Stripping |
The material (sand, clay, soil, etc.) overlying a rock of
economic value, which must be removed before
quarrying. |
| Subjoint |
Minor joints diverging from or parallel to the regular
joints. |
| Syncline |
A geological term for the trough part of a wave-like sheet
or bed of rock. |
| Till |
A mixture of clay and bowlders deposited by
glaciers. |
| Tillite |
Special name for the material of the till. The evidence
that the clay and pebbles or boulders are of glacial
origin is in the parallel striation of the pebbles or
boulders owing to their having been rubbed against a rock
while fixed in the moving ice. |
| Toeing-in |
Quarrymen's term for the wedging in of the end of a
granite sheet under an overhanging joint, probably in
consequence of the faulting of the sheets along the joint.
It is also applied to the overlapping of lenticular
sheets. |
| "Toenails" |
Curved joints intersecting the sheet structure, in most
cases striking with the sheets, in some differing from
them in strike 45° or more. |
| Twin Crystals |
Two adjacent crystals which have formed with the poles of
their main axes in opposite or different directions. |
| Weathering |
The decomposition of a rock owing to the action of the
weather. |
| White Horse |
Term used by quarrymen to denote a light-colored gneiss,
aplite, or pegmatite. |
| Wollastonite | A mineral consisting of silica 51.7 per cent and lime 48.3 per cent. It commonly results from the metamorphism of calcareous rock or marble where in contact with an igneous rock. |
Commercial use of material within this site is strictly prohibited. It is not to be captured, reworked, and placed inside another web site ©. All rights reserved. Peggy B. and George (Pat) Perazzo.