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GLOSSARY

Glossary of terms used in marble, limestone and slabs market

BLOCK: a physical unit of production of a quarry, namely the primary objective of quarry operations. Blocks are classified on the basis of their requirements in volume, dimensions, shape and aesthetic-chromatic properties.

CUTTING FRAME BLOCK: a block with no structural defects, having a regular form, with optimum volume and dimensions for cutting on the cutting frame.

UNFORMED BLOCK: a block with an irregular geometry that departs from a parallelepiped shape, which is more suitable for cutting on cutting blocks/cutting centres. Also shapeless block.

SQUARED BLOCK: a block that has been reduced to a regular geometric shape, tending towards the parallelepiped.

SEMI-SHAPELESS BLOCK: a block with a limited number of flat and regular faces, or having an only partially squared shape.

SLAB: semi-processed flat block with two principle faces, which are nominally parallel, and with non-trimmed sides. Characteristically it has a dimensional ratio between length and width between 1 and 8 and between width and thickness of over 10. The thickness is generally between 15 and 40 mm.

CE: European Community marking, which is placed on all products that conform to Directive specifications, including products in natural stone. The CE marking is applied by the producer, under his own responsibility, and guarantees purchasers that the product satisfies specific requirements.

QUARRY: the physical site where all processing and extraction from a deposit takes place. This includes the faces of excavation, the large squares, the ramps, the machinery, the dump and various fixed and mobile infrastructures.

MARBLE: metamorphic rock containing over 50% of carbonate calcites and/or dolomites and/or aragonites. It is indicated as pure if the carbonates exceed 95% and impure in all other cases.
Any compact rock, which is strong and can be polished, whose hardness exceeds the values of 4 / 4.5 on the Mohs scale. Commercially, the term includes, in addition to marbles in the strictest sense, calcareous stone, alabasters, cipolin marble, dolostones, onyx, serpentinites, etc. Also Commercial Marble.

LIMESTONE: calcareous rock in the widest sense. In Anglo-Saxon nomenclature this term is often used to distinguish a non-crystalline marble (namely a calcareous stone = limestone) from a crystalline marble (metamorphic stone = marble).

QUARTZITE: a metamorphic stone, 80% of which is made up of quartz, which is often easy to split into slabs or sheets.

TRAVERTINE: carbonatic sedimentary rock of chemical origin, with a characteristic cemented vacuolar structure. Travertine originates due to precipitation of calcium carbonate from saturated water, or due to encrustation by aglae and bacteria.

SANDSTONE: clastic sedimentary stone, made up primarily from fragments of detritus and mineral granules, having dimensions between 1/16 mm and 2 mm.
There are a great number of types of sandstone, depending on the genesis, structure and composition: eolianite, arkose (feldspathic-quartz sandstones) and lithic arenites (which may also be calcareous containing calcite or aragonite), etc.

ONYX: A variety of chalcedony, generally not glossy; white or pinkish in colour, turning to greyish brown. If present in calcareous stone in the form of nodes, it takes the name of flintstone. This should not be confused with calcareous onyx, from which practically all commercial materials defined as onyx is made.

GRANITE: magmatic intrusive rock, with an acid chemism, made up of quartz, potassic feldspar, plagioclase, mica and accessory minerals.
Any compact rock, which is strong and can be polished, whose hardness exceeds the values of 4 / 4.5 on the Mohs scale. Commercially, the term includes almost all magmatic rock, in addition to actual granites: gneiss, crushed siliceous stone, siliceous metamorphic stone, etc. Also Commercial Granite.

CALCIUM CARBONATE: made up primarily of carbonatic stones such as marbles, limestones, travertines, cipolin, etc. Chemical formula: CaCO3.

FRAME: Primary cutting unit, equipped with multiple blades, used to saw stone blocks. The frame consists of a blade-holding frame, a structure that supports the guides, an electric motor+flywheel+connecting rod-crank group, which provides movement to the frame, and a block-holding platform.
Frames can be distinguished as: a) marble frames, with straight kinematics, diamond blades and only water cooling; b) granite frames, with pendular/semi-straight kinematics, non-diamond blades and spraying with turbid abrasive material. Also multiple blade frame, Diamond cutting multiple blade frame, alternative frame.

SINGLE BLADE: primary cutting unit with a single diamond-cutting blade (sometimes double) used for squaring, or subordinately for the production of slabs of medium-to-high thickness. Consists of a portal structure, where a blade is installed that operates with an alternating and descending movement on the underlying block. Also Single Blade Plant, Single Blade Frame.

MILLING UNIT: a diamond-cutting tool with a threaded attachment, or shank, suitable for various types of operations (boring, cutting, shaping, engraving, etc.).
A diamond disc machine used to trim and cut to semi-processed dimensions. It may be manual, automatic, with variable geometry, single or multiple discs. Also Miller, Cutter, Sectioning Unit Trimmer, Miller-Cutter, Sawing machine.

POLISHING/DRESSING LINE: a succession of machines designed to smooth and polish surfaces, both with a continuous cycle (no interruption in input of the material to be processed), or discontinuous cycle (interruption of input of material to be processed). Also continuous transformation line, marble chip line, slab line.

MARBLE CHIP: finished product with standardised measurements, having a thickness of less than 12 mm and normally with a fixed form (30 x 30 cm, 60 x 60 cm, etc.). This material requires laying in traditional mortar or binding material and is packaged independently from the place of installation, ready for installation.

ROUGH MATERIAL: generically, this refers to a rough block, as the raw material for the stone chain of production. In a more specific sense, it refers to products or semi-finished products (slabs, sheets) with no surface finishing. Also Rough.

POLISHING: polishing process, through milling, with which brightness and a mirror polish is conferred to a previously smoothed surface. The process employs fine grain abrasives. Faces, sides and heads of the material are polished. Also Cleaning.

DRESSING: surface finishing through milling for the purpose of creating a smooth, but not mirror polished surface. This process is performed with finer grain abrasives than are used for squaring but greater grain than is used for polishing.

BRUSHING: surface treatment with the use of special flexible abrasives.

FLAMING: surface treatment with which a rock is subjected to a high temperature thermal process (2000/2500° C). This determines a "crater-like" roughening of the surface, detaching minute scales. It is effective on silicate rock, and is more rarely effective on carbonatic stone. Also deflaming, thermal splitting, flame treatment.

TUMBLING: antiquing process of stone elements with tumblers and similar machinery. The process may be performed dry or wet, with or without the use of abrasive substances.

SANDING: surface finishing with impact, leaving traces of points, realised by projecting a composite mixture at high pressure and high speed, containing an abrasive agent (sand, corundum, grains, glass spheres) or a combination of appropriately dosed abrasives, in both cases with or without water. The process is performed with sanding machines.
In the past, the surface treatment was obtained manually by dry sanding of the stone with silicate sand, blocks of granite, corundum grains or silicon carbide.

SCRATCHING: impact surface treatment with a linear trace. Realised manually with pointed tools of various types or with scratching machines. The treatment consists of alternating grooves and crests with a sub-parallel or curved orientation.


SOURCE: “ Primavori P. (2004) – Stone sector lexicon – Giorgio Zusi Editore, Verona”.

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