As natural stone is generally referred to all the rocks , similar to those found in nature, to extent that they are considered an economic good or acquires. Natural stone as a sawn or hewn product is called natural stone , undersized natural stone as quarry stone or crushed stone and as field stone .
A mountain made of stone or a rock in nature is certainly colloquially correctly referred to as natural stone . Mineralogists and geologists only use the term rock for natural stone ; and they define rock as a "mixture of minerals". If natural stones are considered or processed economically, it is natural stone or quarry stone . The rules of technology for the processing of natural stone by stonemasons and stone sculptors who process stone are written down in Germany in DIN 18332, among others. The term natural stone is customary in the trade. The natural stone DIN does not apply to road construction and paving work made of natural stone. In linguistic contrast to natural stone, there are man-made stones, for example bricks . These are also known as artificial stones.
Occurrence of natural stone
The natural stone used today mainly in Europe come mostly from India, China, South Africa, Brazil, Italy, Turkey, Spain and Scandinavia. The largest regional mining area is around Rustenburg in South Africa , where the commercial variety Impala , a gabbro , is mined. There are regional rock deposits in almost all federal states in Germany; one of the most important economically used deposits is the " Jura marble ", a limestone in the vicinity of Eichstätt .
The natural stone used in the construction industry mostly comes from quarries and is rarely extracted in Germany from gravel pits. Sometimes they are also collected on the surface of the earth as reading stones for natural stone masonry .
Designation of the natural stones
With the use of natural stone, which has been practiced for thousands of years, it is common to name the respective variety after the place of origin or its region of origin (e.g. Giallo numidicum ). Certain conspicuous optical properties also led to pictorial synonym names , such as " Cipollino marble" (onion marble) or "Mandorla marble" (almond marble for lime lumps ). These names were used for rocks with comparable decorations, regardless of their geographical origin. The situation is similar with some modern petrographic names (e.g. breccia - broken rock).
Sometimes historical contexts also played a role in the use of the name (e.g. Giallo antico ), but these do not always make a clear reference to the mining site. In the Renaissance and Baroque periods names can be observed that have an ancient reference, although the material referred to did not come from the mining site at the time of antiquity.
The choice of trade names for natural stones is just as much a part of the cultural richness of human history as the testimonies left behind from these materials themselves. It can be seen as a matter of course and enrichment that mining companies and processors sometimes choose a sonorous name for a type of stone, sometimes about the Adapted to language habits or even completely changed them for centuries. The name variants of rocks that had been used for a long time were always subject to linguistic, fashionable, technical, economic or political influences. The situation is comparable to the changes in family and place names.
Today it is a matter of course in linguistic terms that different names are used around the world for individual types of natural stone. Even the difficulty of speaking regional names makes modifications seem sensible and is used in this sense. It is often difficult to clarify from Europe why different names are used (differentiation of varieties in quarries, differentiation of varieties in neighboring quarries, regional linguistic peculiarities).
In individual cases an attempt is made to establish a distribution monopoly by assigning a name. This is expressed by the fact that, when an offer is requested, only a very specific type of natural stone is to be offered, which is only available to one supplier. Alternative varieties are not allowed to be included in the bidding process, because then there is a risk of exclusion from the bidding competition. This means that alternative suppliers and alternative types of stone are excluded from competitors. Some suppliers of natural stone types make use of the trademark law in the above sense . The result is that, for example, the use of the name of the natural stone type Ajax , a Greek marble, is only allowed to certain suppliers and that such use or offer by other suppliers constitutes a violation of competition law.
The choice of the trade name for natural stone often appears arbitrary and placed at the discretion of the manufacturer or supplier. There are numerous misleading trade names such as the trade name Belgian granite , which is not granite but a limestone , or a natural stone Caribian Blue , which is not broken in the Caribbean but in Scandinavia . In some cases, the reasons for choosing a name are understandable.
After the entry into force of the European standards EN 12670: Natural stone - Terminology and EN 12440: Natural stone - Criteria for the designation , in addition to the trade name, which can be arbitrarily assigned by the manufacturer as before, also the exact scientific name of the stone, called the petrographic family. Furthermore, the typical rock color and the location of the area or the quarry must be specified as precisely as possible and at least the city or municipality, the area or country in which the quarry is located. In addition, the rock processing, natural characteristics, the petrographic name and the geological age must be stated in tenders. This will make the future use of well-known trade names for similar natural stones from completely different regions and with different qualities much more difficult.
The aim of EN 12670 is to obtain factual and reliable information for a specific type of rock. Whether culturally rooted and regionally justified forms of name can be influenced over the heads of owners, processors and cultural regions will remain a matter of general acceptance.
Definitions of natural stone
Definition according to appearance
Natural stone can be according to their appearance initially divided into
- Loose rock and in
- Solid rock .
Loose stones are not natural stones.
Definition by technology
Natural stones can be prepared by technical processing criteria in
- Hard rock and in
- Divide soft rock .
This classification is suitable for practical use in stonemasonry workshops, in which the stones are manually processed, machine-sawn or ground, for assessing mechanical loads. From this classification, stone experts can in particular determine their use of tools. Ultimately, statements about the usage properties or subsequent installation and use options depend, in general terms, on the chemical attacks to be expected or on the environmental factors to which natural stones are exposed. For example, the soft rock dolomite can be more acid-resistant than the hard rock basanite . Ultimately, water absorption and weathering behavior cannot be derived from the distinction either. The assessment of suitable natural stones before installation requires profound knowledge of geology. Please also note: Natural stone is subject to suitability tests of German or European standards (see below), especially when they are brought onto the market.
Natural stones can be divided into three stone classes according to scientific criteria , according to their origin (genesis).
- Solidification rock ( igneous rocks ): Solidification ( crystallization ) of magma from the interior of the earth forms igneous rock . A distinction in plutonic rocks , created the (km> 5) in the depths of the earth as a plutonic rock, Subvulkanite that are cooled at depths from 0 to 5,000 meters and in volcanic rocks are of volcanic origin (igneous rock).
- Sedimentary rock (sedimentary): By the deposition or formation of sediments at the earth's surface caused by pressure and possibly temperature sedimentary rock .
- Transformation rock (metamorphic rocks ): Transformation under certain pressure and temperature conditions creates metamorphic rocks .
In the natural sciences only the term rock is used. This category cannot be transferred to natural stone, as z. B. Salt rock is scientifically classified as rock. The installation of salt rock would have fatal consequences in the building industry for many reasons and it is therefore not used in the field of technology. The same applies to other rocks according to scientific categorization such as chalk , kieselguhr , anhydrite , natural gypsum , etc.
Use of natural stone
Use in everyday life
Natural stones are used in industry ( cement production , crushed stone, granulates), in horticulture , interior construction ( facade cladding , kitchen countertops , vanity units , stairs , flooring , window sills , ashlar in general), in tomb production, for exterior facades and in restorations as well as in used in stone carving (monuments, sculptures ) and as natural stone masonry . If the natural stone is used as aggregate , these products are called artificial stone .
Natural stones are mined in quarries and then sawn to size in stone processing companies and the surfaces are processed.
Unevenness, color differences and inclusions cannot be prevented with natural stones and are what make a natural stone so attractive.
The possible designs of the stone surfaces of natural stone depend on a number of factors, such as the stone family, the thickness of the material, the nature of the individual minerals in the stone, customer requirements, etc. Natural stone has a wide range of colors and surface designs that cannot be found in any artificial material can be achieved. Natural stones with the same or similar appearance can have very different technical properties. A cheap granite can have almost the same appearance as a high quality granite. A common type of marble from Carrara, such as Carrara C , can “rust”, another Carrara C cannot, despite the same appearance and the same laying, the yellowish discoloration does not occur. The technical data are also very different, above all in terms of water absorption and strength. The appearance alone does not say to what extent a stone is suitable for a specific purpose. The various sensitivities and risks cannot be seen from the appearance.
Calcareous natural stones (limestone and marble), gneiss, clay slate are sensitive to acids and require different care and cleaning than other natural stones when they are used as flooring. Granite and basalt are very hard, firm and often dense natural stones. They are often used outdoors where there is a lot of traffic. Limestone and marbles are less hard and are mostly used indoors or are used to create sculptures. Their aesthetic effects are crucial. Nevertheless, in many European countries there are enough examples of any use of all types of rock. The question of suitability for a particular purpose is also a personal point of view. All materials show their typical signs of aging through use.
With a few exceptions (e.g. oil shale ), natural stone belongs to fire class A. Only in public buildings are cantilevered stairs made of natural stone prohibited.
A major advantage of natural stone over other materials is that the extraction and processing of natural stone requires significantly less energy than other materials (e.g. ceramic tiles). Furthermore, natural stone is unproblematic in terms of disposal, as it contains fewer pollutants.
In a sustainability study of the life cycle assessments of facade constructions with natural stone and glass, commissioned by the German Natural Stone Association (DNV), it has been proven that natural stone is more advantageous.
Roman masonry from Hadrian's Wall in England
Sculpture from Prokonnesian marble
Raised bed made of natural stone
Cleaning and care of natural stones
Gentle care is essential to ensure that natural stones retain their appearance for decades. It is important to consider the respective type of natural stone with its specific properties and the environmental and usage influences it should or is exposed to. Due to the very different mineral composition of the rocks and the different natural stone surface treatments , there are highly differentiated manifestations of wear and soiling. Cleaning and care must be adapted in accordance with credible technical information.
Extraction and processing of natural stone
Extraction of natural stone
The extraction of natural stone in quarries is now mainly done using wire saws and cutting and only in exceptional cases with explosive explosives. Wire saws and scrapers saw loosening joints in the rock. If the stone blocks are too big or too misshapen, they can be formatted to the appropriate size with stone splitting tools or wire saws. The raw blocks are transported within the quarry either with lattice boom cranes or, today, mainly with wheel loaders . The transport to the stone processing companies takes place by truck.
Processing of natural stone
In the stone processing companies, the raw blocks are sawed by gang saws into so-called non-dimensional panels, usually 2, 3 or 4 cm, depending on the desired thickness. The sawn panels are then ground or polished in automated production lines. After this work step, stone saws cut the panels to the appropriate size in width and length. A special way is the production of natural stone tiles in 10 mm thickness, which are cut with special sawing machines, such as B. multi-blade stone circular saws or with saws that drive several saw blades with different saw blade diameters.
If rough blocks made of hard stone are divided into tranches (tranche is a term defined by DIN for stone slabs from 8 cm thick) for the purpose of making tombs, circular log saws are used that drive circular saw blades with a diameter of up to 3 to 4 m. The circular block saws have the advantage over the frame saws that they saw better flatness values. This has the advantage that individual subsequent work steps up to polishing, which would otherwise be necessary, can be skipped.
The surfaces of large panels are usually polished, the invisible reverse side remains rough with saw marks. Your visible surface is also processed differently depending on the intended use, here the slip resistance plays a role, but also design considerations. Unmeasured slabs (3.20–3.60 m (long), 1.60–2.00 m (high)) made of domestic and international natural stone are sold by natural stone dealers to stonemasons who, according to their orders, saw them to the appropriate dimensions with stone saws .
Usual formats of natural stone slabs
Floor covering associations and panel formats:
There are more than 300 associations for natural stone flooring:
- Roman association with up to 16 different plate formats
- Membrane covering (slabs of different lengths with the same slab width (e.g. 15, 20, 25, 30 cm) are laid in longitudinal sheets)
- Floor with square tiles
The following panel formats are standardized for floor coverings :
- Floor covering in strips: 1.5 cm; 2.0 cm, 3.0 cm thick: The panels are different in length, but panel widths of 15.0 cm, 20.0 cm, 25.0 cm, 30.0 cm, 40.0 cm are common.
- Natural stone tiles with a thickness of 10 mm: 30.5 × 30.5 cm; 61.0 × 30.5 cm, 30.0 × 15 cm. Other formats are also available here.
- Natural stone paving : As large stone paving, small paving, mosaic paving between approx. 18 × 18 and 4 × 4 cm, or as a stone slab, also in natural form.
Formats for commercially available raw stone blocks:
- 3.20–3.60 m (length), 1.60–2.00 m (height), 1.20–1.60 m (width)
Formats for stairs are individual:
- The stair tread plates are normally 3 cm thick, the stair riser plates 2 cm thick. With bolt stairs made of natural stone, depending on the statics, two 3.0–3.5 cm thick plates are glued with special adhesives and plastic mats, which ensure the necessary flexural strength of the step plates. In the case of massive self-supporting steps, the statics are calculated according to the existing span and the required step thickness.
Formats for kitchen worktops:
- The kitchen countertops are usually 3–4 cm thick. There are kitchen tops that consist of two plates, with narrow face plates glued to the visible edges. These panels are 2.0 + 2.0 cm thick. Recently there have been stone slabs for the kitchen that are sawn approx. 10 mm thick and are used as kitchen worktops - to save weight.
Edge processing :
- The respective visible surface processing corresponded to the visible edges. In addition to right-angled edges, there are profiled edges such as bevels , round bars , covings and also multi-composite profiles .
- Stone foils are sawn in the 1 mm range, which are deformed and shaped in a special process depending on the type of car and then installed in luxury vehicles.
All other formats can be made individually.
Natural stone surfaces
Stone surfaces are requested and manufactured according to optical and functional aspects. In the following, some stone surfaces that have been produced either by hand or by machine or with tools are presented.
Sharpened stone surface made of sandstone
Pointed stone surface ( Beucha granite porphyry ), (pattern approx. 25 × 15 cm)
Cut stone surface made of Obernkirchen sandstone , pattern approx. 25 × 15 cm
Polished stone surface of Serizzo ( gneiss ), Switzerland , (pattern approx. 25 × 15 cm)
Flamed stone surface ( Ruhr sandstone ), (pattern approx. 24 × 14 cm)
Standards for natural stone
- DIN 18332 Part C: General technical contract conditions for construction works (ATV); Natural stone work
- DIN 18516-3 external wall cladding ventilated; Part 3: Natural stone, requirements, dimensioning
- ÖNORM B 2213 Stone masonry and artificial stone work - work contract standard
- Standard SIA 118/246 General conditions for natural stone work
- Terms and definitions:
- EN 12670 natural stone - terminology
- EN 12440 natural stone - criteria for the designation
- Test standards for natural stone:
- EN 1341 Natural stone slabs for outdoor use - Requirements and test methods
- EN 1342 paving stones (made of natural stone) for outdoor areas - requirements and test methods
- EN 1343 Natural stone curbs for outdoor areas - Requirements and test methods
- EN 1925 Test method for natural stone - Determination of the water absorption coefficient due to capillary action
- EN 1926 test method for natural stone - determination of compressive strength
- EN 1936 Testing of natural stone - Determination of the true density, the bulk density, the open porosity and the total porosity
- EN 12370 Test method for natural stone - Determination of the resistance to crystallization of salts
- EN 12371 Testing of natural stone - Determination of frost resistance
- EN 12372 test method for natural stone - determination of flexural strength under center line load
- EN 13161 test method for natural stone - Determination of flexural strength under third-line load
- EN 13364 Testing of natural stone - Determination of the breakout load at the anchor pin hole
- EN 13755 Test method for natural stone - Determination of water absorption under atmospheric pressure
- EN 14157 Test method for natural stone - Determination of the resistance to wear
- EN 14231 Test method for natural stone - Determination of sliding resistance with the aid of the pendulum tester
- Product standards:
- EN 771–6 Specification for masonry stones - natural stones
- EN 1467 ingots
- EN 1468 semi-finished products (raw panels)
- EN 1469 finished products, cladding panels (facade panels)
- EN 12057 finished products, tiles
- EN 12058 floor slabs and step coverings
- EN 12059 finished products, stones for solid work (draft)
Depictions on the history of natural stone mining and collections
Like the buildings and monuments built from them, the natural stones have their own history of mining and use. Some institutions provide information about the history and technologies of natural stone mining. They are mainly found in regions with significant stone-mining traditions. In Europe, for several places in Havixbeck, the Baumberger Sandstone Museum in Häslich the show and Museum of the granite industry, the Green Sandstone Museum of Soest , the Lahnmarmor Museum in Villmar , the Stone Museum Solothurn , in Bellignies the Musée du Marbre et de la Pierre Bleue ( Museum of Marble and Bluestone), the Swedish towns of Hunnebostrand and Vånevik each have a Stenhuggarmuseum (Stone Carving Museum), the Museo di Storia Naturale dell'Accademia dei Fisiocritici (Museum of Natural History) in Siena and the Museo del Marmo (Museum of Marble) in Botticino Mattina .
ASMOSIA is an internationally active organization that deals from a scientific point of view with ancient natural stone mining and its applications . Numerous universities continue to conduct research in this sector.
Only a few natural stone collections are publicly accessible worldwide. This includes the collections of the Natural History Museum in Vienna, the German Natural Stone Archive and the Smithsonian Institution . Today's building and decorative stone collection of the Natural History Museum of Vienna was donated in 1878 and was further built up by Felix Karrer . By 1890 it already comprised 7,000 samples. They are all among the largest of their kind. In addition to numerous other institutional collections, there are also private collections with special collections. Often smaller collections are dedicated to specific and regional topics.
Natural stone trade associations
In Germany, the professional associations for natural stone are divided into industry and craft. There is the Federal Association of German Stonemasons based in Frankfurt am Main , which is divided into 16 regional guilds. The federal association represents the interests of the stonemasonry and stone carving trade. The German Natural Stone Association, based in Würzburg, organizes the German stone industry. Both associations have a common umbrella organization in the Central Association of the German Natural Stone Industry (ZDNW) .
The Association of Swiss Sculptors and Stonemasons - VSBS in Switzerland represents the profession-specific interests of the sculptor and stonemason trade in public and towards the authorities. The Swiss Natural Stone Association - NVS organizes the natural stone processing industry. In Switzerland there is the working group Pro Naturstein Schweiz as an umbrella organization based in Bern , which is made up of craft and industry as well as other associations such as the pavers and the natural stone associations of French and Italian-speaking Switzerland.
The craft businesses in Austria are organized in the federal guild of Austrian stonemasons at the Austrian Chamber of Commerce . The stone industry in Austria is represented in the Association of Austrian Natural Stone Works based in Linz .
In Europe several countries have come together to form the natural stone association EUROROC (European Federation of Dimension Stone), which takes care of the interests of the European natural stone industry. These are the natural stone associations of the countries Germany, Finland, Italy, Norway, Austria, Poland, Spain, Sweden and Switzerland.
Natural stone fairs
There are numerous natural stone fairs in Europe. The two largest fairs are the natural stone fair “stone + tec” in Nuremberg and the natural stone fair “MARMOMACC” in Verona . Another trade fair takes place in Carrara every two years . In England In addition is the "Stone Show" in London and in Poland the "Internation Fair of Stone and Stone maschinery" in Wroclaw (Breslau)
A symposium on the subject of "natural stone renovation" has been held every year for 20 years. The organizer is the University of Technology, Stuttgart.
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- ↑ Günther Mehling (Ed.): Natural stone lexicon . Callwey, Munich 1993, pp. 83, 384, 627
- ↑ Arnd Peschel: Natural stones . Verl.d. Basic industry, Leipzig 1983, pp. 349, 373
- ↑ Life cycle assessments of facade constructions with natural stone and glass ( Memento from April 23, 2015 in the Internet Archive ), ed. v. German Natural Stone Association, accessed on October 19, 2014
- ↑ Schroeder: Stones in German Cities , p. 24
- ↑ Felix Karrer: Guide through the building material collection of the Imperial and Royal Natural History Court Museum in Vienna . Vienna 1892, p. IV
- ↑ Carrara Municipal Marble Museum
- ↑ Musée du Marbre in Bagnères-de-Bigorre ( Memento of May 18, 2009 in the Internet Archive ) (French)
- ^ Official website of the Federal Association of German Stonemasons
- ↑ Official website of the Federal Guild of German Stonemasons
- ^ German Natural Stone Association - DNV ( Memento from September 5, 2011 in the Internet Archive )
- ^ Official website of the Association of Swiss Master Sculptors and Stonemasons - VSBS
- ↑ Official website of the Swiss Natural Stone Association - NVS
- ↑ Official website of Pro Naturstein Schweiz
- ↑ Official website of the Association of Austrian Natural Stone Works
- ↑ EUOROC - European Natural Stone Association
- ↑ Natural stone fair "stone + tec" in Nuremberg, Germany ( Memento from October 29, 2007 in the Internet Archive )
- ↑ MARMOMACC natural stone fair in Verona, Italy ( Memento from July 4, 2007 in the Internet Archive )
- ^ Natural stone fair “CarraraMARMOTEC” in Carrara, Italy
- ^ Stone show in London, England
- ↑ Natural stone fair International Fair of Stone and Stone Maschinery in Wrocław (Breslau), Poland
- ↑ http://www.hft-stuttgart.de/Studiengebiete/Bauingenieurwesen/Bachelor-Bauingenieurwesen/BBI_Aktuell/index.html/de