marble

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Marble Laocoon group in the Vatican Museum

Marble (from Latin marmor from ancient Greek μάρμαρος mármaros "[shiny] boulder, stone; marble", this derived from μαρμαίρειν marmaírein "shimmer, shimmer") denotes carbonate rocks of various compositions, which mainly consist of the minerals calcite and dolomite and, due to their material properties, particularly are used for sophisticated architecture or for the production of sculptures.

There are different meanings of words for marble :

A number of significant buildings and works of art are made of marble. Marbles are used for floor and stair coverings, table tops, wall tiles, sinks and facade panels. The extraction of marble, which has been practiced for thousands of years, is still a complex process today.

Explanation of terms

Pietà by Michelangelo in St. Peter's Basilica in Rome
Group of figures by the sculptor Jean-Jacques Pradier (Musée du Louvre in Paris)

The term marble has different meanings.

Petrographic term

In the petrographic sense, marbles are metamorphic rocks that contain at least 50 percent by volume of calcite , dolomite or, more rarely, aragonite . Many are made up of almost only one carbonate mineral (i.e., are mono-mineral). Marbles have undergone metamorphosis under high pressure or high temperature and have become this through marbling. Pure marble is composed of at least 95 percent by volume calcite and / or dolomite. Marbles labeled as impure can contain 5 to 50 percent by volume of silicate minerals; these are called silicate marbles. Many belong to the paragestones, that is, they emerged from sedimentites (deposit rocks).

Marbles that have undergone a second metamorphosis and were already marbles and thus metamorphites and those that arise from the conversion of carbonatites are an exception . In geology, carbonatite is a rare igneous rock that contains more than 50 percent by volume, but typically 70 to 90 percent by volume, of carbonate minerals. Occasionally, metamorphic areas occur in sequences of carbonate sedimentary rocks. This makes it difficult to classify the entire unit as marble, dolomite or limestone.

Agglo-marbles as well as artificial and stucco marbles , which are made by human hands , are not marbles in the petrographic sense .

Non-petrographic definitions

Concept of culture

In German-speaking countries, countless limestones , limestone breccias , dolomites , travertines , onyx marbles and in some cases other rocks that contain little or no carbonates are called marbles, for example serpentinites and ophicalcites . Marble as a cultural term has been widespread for centuries in the literature on the subjects of architecture, interior design, applied arts, art history and other areas in a petrographically incorrect application without this having any consequences. This can also be explained by the fact that a geoscientific understanding of rock metamorphoses did not develop until the second half of the 19th century , according to which actual marble differs from limestone through geological transformation processes.

In Italy, polished granite and gneiss are occasionally sold under the name marmi (plural form) , although their texture is often only remotely comparable to carbonate rocks and they have a completely different chemical and mineralogical composition than marbles. The use of the word marble (Italian: marmo, French: marbre, English: marble, Spanish: mármol, Portuguese: mármore, Swedish: marmor, Russian: мра́мор, Czech: mramor, Polish: marmur, Hungarian: márvány ) as a comprehensive cultural term common in almost all countries. In France, the differentiation is somewhat more pronounced, in that the words calcaire (German: limestone) or just pierre (German: stone) are clearly accentuated for all types of limestone . Nevertheless, no exact petrographic distinction is made in everyday French language. However, some limestones are also known as marbre (e.g. Marbre Rose de Guillestre, Marbre de Campan or Marbre de Vérone ).

Economic term

Filigree marble vase

While the arbitrary use of the term marble in cultural life has no consequences, this can have consequences in the economy. In business life, limestones that can be polished, such as the so-called Jura marble , a limestone, are definitely offered as marble. The stone processing industry takes into account in sales talks that customers in German-speaking countries mostly only know granite as an extremely hard stone, and marble as a supposedly expensive stone. When a sale is concluded, a stonemason is required to expressly point out the difference between limestone and marble, for example, in accordance with the currently applicable DIN EN standard of 2018 and corresponding case law .

Emergence

Marble is created by metamorphic transformation of limestones, dolomites and other carbonate-rich rocks under the influence of high pressure and temperature as a result of high sediment load and / or tectonic subsidence ( regional metamorphosis ) or through heating in contact with molten rock ( contact metamorphism ). If dolomites have been converted, one speaks of dolomite marble.

In the contact metamorphism intrude granitic magmas or other into the upper crust. If they do not reach the earth's surface, they remain in the earth's crust, cool down in magma chambers over millennia and solidify into granite or igneous rocks of similar composition. During this phase of cooling, rocks rich in carbonate in the vicinity of the granite pluton can transform into marble. In a contact metamorphosis, pressures of up to 10 kilobars and temperatures of over 400 ° C prevail.

During regional metamorphosis, large amounts of rock are converted under pressure and heat without contact with magma. These processes are very slow. In this way, for example, marbles with a directional structure (rough-gap panels can be obtained). The preferred direction of the split is mostly orthogonal to the direction of the previous principal stress. Since marbles deform ductile above a certain pressure and temperature level , they can show folds and flow structures, which are visible as marbling if the secondary mixture components are inhomogeneously distributed (e.g. in Saillon marble from Saillon , Switzerland). In geology , ductile means that rocks, especially those of the lower continental crust , do not become brittle under tectonic stress (heat and pressure) , but rather plastically deform.

Characteristics and mineral inventory

Marble, handpiece

Marbles are usually medium to large crystalline, the individual calcite crystals vary little in size and can often be distinguished with the naked eye. However, there are also extremely fine crystalline marbles such as the Statuario variety from Carrara, which is very popular with sculptors. The characteristic of crystallinity also applies to marbles, the parent rocks of which had a sedimentary grain structure, such as the majority of meta-limestones and meta- marlstones (a meta-rock is, for example, a sandstone made from a sandstone, etc.). Due to the crystalline structure, the pore space of the marble is small, which leads to a high frost resistance of many types of marble, but it cannot be generalized for all types. A typical characteristic of marble is the lack of fossils . Marbles can also be recognized optically by the fact that individual calcite crystals glitter in the cleavage surface, depending on the direction of the incidence of light (see illustration).

Material admixtures in the original rock lead to the typical decor of many marbles, the so-called marbling. Marble comes in different colors - from striped black to yellow, green, pink to white marble. Red to reddish marbles are colored by hematite , yellow to brown by limonite , slightly bluish and gray-blue marbles by graphite , carbonaceous substances or bitumen, and green marbles by chlorite or serpentine minerals. Multi-colored marbles contain different mineral additions and / or different crystal formations. There are no uniform black colored marbles.

The white marble, as it is found among others near Carrara in the Apuan mountain valleys in Italy and in the Krastal in Austria , is in high demand. In Germany there are few marble deposits that are economically viable for natural stone, for example the Wunsiedler marble in the Fichtelgebirge . In the Ore Mountains near Hammerunterwiesenthal, calcite and dolomite marble is mined, which is mainly processed into crushed stone and the finest rock flour and mainly used as an aggregate for industry. Due to the high density of fractures and faults, blocks of sufficient size cannot be obtained that are suitable for economic use in natural stone production. Crottendorfer marble had acquired a temporary significance as a sculptural material .

Typical dolomite marbles are those of the Rauris Valley in Austria and the Thassos marble from the Greek island of the same name. A specialty is the so-called Cipollino (Italian for "onion"), a marble whose decor is layered like an onion.

The white marbles are translucent. It shimmers through a type of marble from Paros up to a stone thickness of about 3.5 centimeters and through that from Carrara up to about 1.5 centimeters. The so-called translucency depends on the crystal structure and the pore radius distribution. The denser a marble, the more translucent it is. A typical example is the marble quarried from Turkey near Afyon .

Extraction and processing of marble

Quarrying Carrara marble
A wire saw formats a rough block of marble in a quarry in the Carrara Mountains
A Schräme with a 5 meter long sword, a kind of chainsaw, cuts raw marble blocks from the walls of the quarry
View over a Karibib marble mine (2018)
22 ° 6 ′ 16 ″  S , 15 ° 48 ′ 48 ″  E

In the past, marble was extracted using fissures with lifting bars and wooden wedges swelled with water. Iron wedges were only used later .

Marble has been mined in Europe for a long time. On the Greek island of Paros has been around since the 7th century BC And in Carrara since the 2nd century BC. Marble quarried. Little changed in the extraction technology for marbles until the Renaissance . From the Renaissance to the 1960s, explosives were sometimes used that were placed in boreholes. The use of explosive explosives resulted in a large amount of rock debris and the rock was in some cases considerably damaged by the explosive effect.

Technical innovations on a grand scale in marble processing came from Carrara in Italy. Around 1815 the Italian worker Giuseppe Perugi invented the first frame saw for natural stone with several saw blades, which was driven by high-speed water wheels. The Swiss Carlo Müller continued to improve this technique until in 1831 the French Nerier introduced stone frame saws with up to eight saw blades, which made it possible to produce several large-format marble slabs one centimeter thick; the process was awarded a prize at the World Exhibition in Paris in 1867. In 1870 there were already 40 sawmills using this technology in Carrara, 15 in Massa and 26 in Seravezza . In 1895, in Carrara, Italy, spiral wire was first used to saw out stone blocks, which was driven by diesel engines. Not only water was used to cool the wire, but the steel ropes were hundreds of meters long and were led through the quarries via pulleys behind the outlet from the kerf, so that they could cool down in between. Later the diesel engines were replaced by electric motors. Today marble is no longer made with the above-mentioned long wire saws, but with short wire saws that only carry so-called diamond wires several tens of meters long, or they are sawed out with cutters .

Wire saws guide long steel cables densely covered with carbide beads through the marble layers in the quarry or through the raw blocks in the factories , as required . There are industrial diamonds in the hard metal beads. A constant stream of water cools the saw ropes.

In Italy, saws usually cut loose joints up to a length of 4 to 5 m in the marble rock layers, which reach a working depth of about 2–2.50 m. Schrämen are large mobile chainsaws that work without water cooling. Furthermore, rough blocks are further formatted with pneumatic hammers and stone splitting tools as required.

So-called release cushions made of sheet steel are inserted into the loosening joints that the wire saws and trimmers make, which are filled with either water or air pressure. In this process, the blocks are pushed out of the stone wall for further transport. In the quarry, the loosened blocks are moved with huge wheel loaders and then loaded onto trucks for further transport, provided they are not processed further on site.

The raw marble blocks are cut into panels with gang saws with between 80 and 120 saw blades, then the visible sides are ground and, if necessary, polished. Marbles for use in ashlar are cut to the desired size with stone saws .

The polishing process of the marble and other natural stones made since the industrial age are increasingly using mechanical means, with hand-held and fully automated machine technologies are used. This is particularly true of surface polishing, which has been fully automated in European processing centers since around 1975. For the polishing of three-dimensional objects with irregularly curved small surfaces, such as in the work of a sculptor, small mechanical tools and manually operated processing means are required. The actual polishing process is largely similar to the necessary and previous grinding processes. A mostly rotating sanding pad carries industrially produced and standardized abrasive bodies that contain abrasive components with defined grain sizes in a soft binding compound. These grinding wheels can be ring-shaped or cuboid. The plate with the attached grinding tools, which is applied to the marble surface with the necessary pressure and rotation speed, removes the slightest unevenness of the already very finely ground marble surface. The finer and gentler this process is carried out, the shinier the treated surface will be. The polishing zone is cooled with water (other coolants are also used for individual rocks) so that the heat development does not create any microcracks in the rock crystals, which would reduce the result, but also to remove the resulting grinding sludge. Today, aluminum oxide ( corundum ), silicon carbide , tin oxide or a mixture of magnesium oxide and magnesium chloride are usually used as abrasive materials in the grinding tools . The polishing agents used in historical craft techniques, suitable earths (e.g. triple ), clover salt or substances produced in manufactories (e.g. polishing red ) are only used in special cases today; also diamond powder . In addition, the grinding tools contain thermosetting plastics, which have a beneficial effect on the end result during the polishing process. In the final treatment (finish) of the polishing process, if necessary, dissolved resins or waxes can be applied with rotating felt discs. The use of auxiliary and polishing agents as well as the technological conditions depend on the type of rock in question over the entire course of the surface treatment. In other words, they are coordinated and used by means of tests and user experience.

Use and durability

A marble torso is created
Carrara marble washbasin
Bench (dark blue is type Bardiglio , light is Carrara marble C ) and tree container on the Piazza Alberica in Carrara

Buildings and sculptures from ancient Greece such as the Acropolis and the Pergamon Altar , the Nike of Samothrace and the Venus of Milo are made of Greek marble. In the Roman Empire , statues of honor made of marble (so-called ἀγάλματα agálmata ) were reserved for gods as well as the emperor and his family members. Citizens, on the other hand, were generally honored with bronze statues ( εἰκῶνες eikṓnes ). Marble statues of them were only placed in private rooms or on graves. Many works of art from the Italian Renaissance, such as Michelangelo's Pietà , David and Moses, are made of Italian Carrara marble.

Because of its great importance in art history and its very special material properties, which cannot be compared to sandstones and other sediments, the conservation of marble is a separate field of research.

Marbles are in great demand in interior design today. They are used as floor and stair coverings as well as tiles. They are sought-after sculpting materials, especially Carrara marble. Due to their sensitivity to acids such as vinegar , wine, citrus fruits and certain cleaning agents, untreated marbles are not recommended for use in kitchens or as kitchen countertops. It can lead to staining. However, the stain protection treatments silanes and siloxanes are not without controversy due to their composition. Dolomite marble shows a significantly higher resistance to amidosulfonic acid or fruit acids than calcite marble.

Since the mid-1960s, facade panels made of natural stone with a thickness of 30 to 40 mm and an air layer of at least 2 cm have been anchored in front of the thermal insulation behind them . Significant deformations (so-called bowls) have been found on a number of fixed marble slabs on facades, which lead to static problems in well-known marble-clad buildings, such as the Finlandia Hall in Helsinki , the Grande Arche de la Défense in Paris and the Aon Center in Chicago led. The warping results primarily from the moisture in the panels on the front and back, as well as during the day-night cycle and weathering processes on the surfaces with effects at the fastening points. The rounding of the marble has led to the costly replacement of entire facades and to an image problem that was reflected in the sharp fall in production rates in the marble industry. There are definitely differences between the various types of marble that need to be taken into account in specialist planning. Extremely weathered marble facades do not appear to be useful north of the Alps.

In contrast to German-speaking countries, marbles and limestone are naturally used in the Mediterranean countries and in France for kitchen countertops , sinks and other utensils in homes, but also outside (e.g. as curbs, benches or planters for small trees). The acceptance of signs of wear and tear on any material is a question of one's personal attitude towards ubiquitous signs of wear. When installing polished marble floors, matt walking areas can appear relatively quickly, depending on the use. This phenomenon applies to all polished floors made of rocks composed of carbonate minerals. In individual cases, this can also occur with granites.

The absorbency of marbles and limestones, which is often perceived as annoying, is a question of the choice of material. It always depends on the porosity of the respective natural stone. There are marbles and limestones that have a porosity of less than one percent. All marbles are sensitive to acid rain and acids. Individual granites and gneisses also show a specific sensitivity to acids.

Rounded marble stones are used to make stone carpets .

Marble is also used in the finest powder form as an abrasive in toothpaste and as a filler or coating color for high-quality papers or in primers for panel painting , also as a white pigment or white mineral in plasters and wall paints (see also calcium carbonate ). The supply of these branches of industry is carried out by specially selected quarries.

Marble types

Marbles can come in many colors and textures. The images below show a selection of marble types.

  • Colors and textures of marbles

  • Bardiglio, marble, Carrara in Italy, ( Jura ), approx. 20 × 15 cm

  • Cipollino Damascato, silicate marble, Stazzema / Lucca in Italy, (chalk), approx. 22 × 15 cm

  • Estremoz, marble, Estremoz in Portugal, ( Cambrian ), approx. 22 × 15 cm

  • Aksehir black, marble (a marble with a black body and gray to light gray / whitish sprinkles), Akşehir , Anatolia in Turkey, (Triassic), approx. 22 × 15 cm

  • Trigaches, marble, trigaches in Portugal, (early Paleozoic), approx. 22 × 15 cm

  • Kittilä marble, silicate marble, Kittilä in Finland, ( Paleozoic ), approx. 12 × 7 cm

  • Sienese marble, Val d'Elsa in Italy approx. 10 × 7 cm

  • Thiersheim silicate marble, Thiersheim in Bavaria / Germany, approx. 22 × 15 cm

  • Naxos marble , Naxos in Greece, approx. 22 × 15 cm

Marbles of cultural history

Selected larger marble mining regions

Marriage carousel by Jürgen Weber , fountain with marble from Portugal (light sections) and with dark bronze sculptures in Nuremberg

Europe

Asia

  • Turkey: regions Izmir, Muğla, Afyon, Sivas, Akhisar, Antalya, Alanya, Sakarya and Amasya

North America

  • USA: States of Georgia and Vermont
  • Canada: Province of Quebec

See also

literature

  • Karlfried Fuchs: Natural stones from all over the world, discover, determine, use. Callwey, Munich 1997, ISBN 3-76-671267-5 .
  • Jacques Dubarry de Lassale: marble. Occurrence, destination, processing . Deutsche Verlags-Anstalt, Stuttgart, Munich 2002. ISBN 3-421-03409-5 .
  • Luciana and Tiziano Mannoni: marble, material and culture . Munich 1980, ISBN 3-7667-0505-9 .
  • Friedrich Müller : Geology, textbook and reference work on rocks for building construction, interior design, art and restoration . 6th edition, complete Revised, Ebner, Ulm 2001, ISBN 3-87188-122-8 .
  • Dietmar Reinsch: Geology . Edited by Educational center for the stonemasonry and sculpture trade. In: Steinmetzpraxis, The manual for daily work with natural stone . 2nd revised edition, Ebner, Ulm 1994, ISBN 3-87188-138-4 .
  • Gunter Steinbach (Ed.): Rocks, 113 rock groups with numerous varieties . New edited special edition, Mosaik, Munich 1996, p. 204.

Web links

Musée du Marbre et de la Pierre Bleue in Bellignies (France)
Commons : Marble  album with pictures, videos and audio files
Wiktionary: Marble  - explanations of meanings, word origins, synonyms, translations

Individual evidence

  1. ^ Karl Ernst Georges : Comprehensive Latin-German concise dictionary . 8th, improved and increased edition. Hahnsche Buchhandlung, Hanover 1918 ( zeno.org [accessed February 9, 2021]).
  2. ^ Wilhelm Pape , Max Sengebusch (arrangement): Concise dictionary of the Greek language . 3rd edition, 6th impression. Vieweg & Sohn, Braunschweig 1914 ( zeno.org [accessed on February 9, 2021]).
  3. ^ Wilhelm Pape , Max Sengebusch (arrangement): Concise dictionary of the Greek language . 3rd edition, 6th impression. Vieweg & Sohn, Braunschweig 1914 ( zeno.org [accessed on February 9, 2021]; the dictionary does not contain the infinitive but, as is customary in ancient Greek, the 1st person singular indicative present active ).
  4. ↑ Douglas Fettes, Jacqueline Desmons (Ed.): Metamorphic Rocks. A Classification and Glossary of Terms . Cambridge University Press, Cambridge 2007, ISBN 978-0-521-86810-5 p. 170.
  5. ↑ Roland Vinx: Rock determination in the field . Elsevier, Munich 2005, ISBN 3-8274-1513-6 , pp. 400-401.
  6. ↑ Wolfhard Wimmenauer : Petrography of igneous and metamorphic rocks . Enke, Stuttgart 1985, ISBN 3-432-94671-6 , pp. 160-163.
  7. ↑ DIN EN 12440 2018-01 Natural stone - criteria for the designation . In: Baunormenlexikon, undated, accessed on July 29, 2020
  8. ↑ Karlfried Fuchs: Natursteine , page XII, see Lit.
  9. ↑ Friedrich Müller : Gesteinskunde , page 173 ff., See Ref.
  10. ↑ Erzgebirge marble , Hammerunterwiesenthal location. GEOMIN Industrial Minerals, accessed February 10, 2021 .
  11. ↑ Dietmar Reinsch: Gesteinskunde , page 259, see Ref.
  12. ↑ Luciana and Tiziano Mannoni: Marmor, p. 208, see Ref.
  13. ^ Sawing marble
  14. ^ Jacques Dubarry de Lassale: Marble. Occurrence, destination, processing . Deutsche Verlags-Anstalt , Stuttgart, Munich 2002, p. 43
  15. ↑ Günther Mehling (Ed.): Natural stone lexicon . Callwey Verlag , 4th edition, Munich 1993, pp. 424-425
  16. ↑ Franco Cucchi, Santo Gerdol: The natural stone from the Carso . Trieste 1989, p. 103
  17. ↑ Raymond Perrier: Les Roches Ornementales . Edition Pro Roc, Ternay 2004, pp. 547-557
  18. ↑ The marble of the Pergamon Altar was broken on what is now the Turkish island of Marmara not far from the Dardanelles ( Memento from July 6, 2007 in the Internet Archive )
  19. ↑ Götz Lahusen , Roman portraits. Client - Functions - Locations , Wissenschaftliche Buchgesellschaft, Darmstadt 2010, p. 68
  20. ↑ Marble Preservation. Special issue: Preservation of Marbles.] Eds .: Siegesmund, Siegfried; Snethlage, Rolf; Vollbrecht, Axel; Weiss, Thomas. 1999. 213 p., 130 fig., 23 tables, 4 plates, 0.1 x 0. cm (Journal of the German Geological Society, Volume 150, Issue 2). ISBN 978-3-510-66017-9 .
  21. ↑ Study on the curling of facade panels made of marble (PDF; 3.2 MB)
  22. ↑ Thomas Drachenberg (Ed.): Preservation of marble sculptures under Central European environmental conditions = Contributions to the 8th Conservation Science Colloquium in Berlin / Brandenburg on October 17, 2014 in Potsdam = Workbooks of the Brandenburg State Office for Monument Preservation and State Archaeological Museum 32nd Wernersche Verlagsgesellschaft , Worms 2014. ISBN 978-3-88462-356-5
This version was added to the list of articles worth reading on February 11, 2008 .