Rocky strata clearly distinct from other substrata by a stratification joint which is usually fairly soft or even sunken.
Bedding plane
Natural direction of rock sedimentation, not always horizontal.
Breaking down
Action of cutting rough, extracted blocks of stone into smaller elements.
Broach
Metal spike, 0.25-0.35 m long.
Bush hammer
Square-headed hammer tipped with points, used to produce an even surface on a stone.
Cant
Exterior edge of a stone’s surface.
Chamfer
Small bevel made to a corner.
Chisel
Flat-bladed tool which cuts in the natural direction of the stone’s fault-line.
Crinoid
Marine organism, may be seen in abundance in a fossilized state.
Crushing
Action of reducing stone to small fragments.
Downcut
Stone cut perpendicular to its bedding plane.
Draining
Action of emptying out water which has infiltrated a rock. Also known as “dewatering”.
Face
Central area of the exposed surface of a stone.
Face-bedded
Stone set with the stratification vertical.
Geode
Spherical, hollow rock mass lined with crystals.
Glauconite
Silicate hydrate containing iron, a dark green mineral present in certain sedimentary rocks.
Glyptography
An academic subject related to history, involving the study of signs made on stones.
Helical wire
Metallic wires wound into a spiral which cut the rock by dragging sand and water across it.
Joint
Crack in a rock which does not cause the two blocks either side to become displaced.
Karstic
Said of limestone which has been attacked by the erosive action of water on its surface and underground, forming potholes as it infiltrates the cracks.
Lower bed
Lower surface of a stone, to be placed on top of another.
Marble
For those professionally involved with stone, the word marble encompasses various calcareous hard rocks able to take a polished finish. When genuine marble is
specified, it refers only to metamorphic calcareous rocks.
Rough hewing
Method of preparing the shape of a moulding or sculpture starting from a parallelepiped and removing prisms which become increasingly thin, until the definitive volume is reached.
Schistosity
The splitting into layers of certain argilaceous rocks in response to deformation stresses.
Splitting
Action of splitting the stone along the natural lines of the lamellar layers.
Squaring
Action carried out to produce a more or less square sided block.
Stereotomy
Science dealing with the cutting of solid items (stone, wood, etc.);
method of cutting and assembling stones using descriptive geometry.
Stratification
Arrangement of beds or varieties of stone in superimposed layers.
Stylolites
Fine joins in sedimentary rocks, parallel to the layers and marked by a concentration of clays.
Surfacing
Action consisting of levelling all the surfaces of an untreated stone.
Toothed chisel
Mason’s chisel, markedly tapering in form and jagged, generally used for roughing out.
Toothed polka
Hammer with double claws, turned inversely to the handle.
Upper bed
Upper surface of a stone, to serve as a support for a new block.
Wedge
Piece of metal inserted into holes drilled into rock, which is then hammered until the stone splits off (a process known as “channeling”).
