Natural stone - Terminology

This European Standard defines the recommended terminology covering scientific, and technical terms, test methods, products, and the classification of Natural Stones.

Naturstein - Terminologie

Diese Europäische Norm definiert die empfohlene Terminologie für wissenschaftliche und technische Begriffe, Prüfverfahren, Produkte und die Klassifizierung von Naturstein.

Pierre naturelle - Terminologie

La présente Norme européenne définit une terminologie recommandée des termes scientifiques et techniques, des méthodes d'essai et des produits ainsi qu'une classification des pierres naturelles.

Naravni kamen - Terminologija

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2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.Naravni kamen - TerminologijaNaturstein - TerminologiePierre naturelle - TerminologieNatural stone - Terminology73.020Rudarstvo in kamnolomsko izkopavanjeMining and quarrying91.100.15Mineralni materiali in izdelkiMineral materials and products01.040.73Rudarstvo in rudnine (Slovarji)Mining and minerals (Vocabularies)01.040.91Gradbeni materiali in gradnja (Slovarji)Construction materials and building (Vocabularies)ICS:Ta slovenski standard je istoveten z:EN 12670:2001SIST EN 12670:2002en01-maj-2002SIST EN 12670:2002SLOVENSKI

SIST EN 12670:2002

EUROPEAN STANDARDNORME EUROPÉENNEEUROPÄISCHE NORMEN 12670December 2001ICS 01.040.73; 01.040.91; 73.020; 91.100.15English versionNatural stone - TerminologyPierre naturelle - TerminologieNaturstein - TerminologieThis European Standard was approved by CEN on 20 October 2001.CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this EuropeanStandard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such nationalstandards may be obtained on application to the Management Centre or to any CEN member.This European Standard exists in three official versions (English, French, German). A version in any other language made by translationunder the responsibility of a CEN member into its own language and notified to the Management Centre has the same status as the officialversions.CEN members are the national standards bodies of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece,Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMITÉ EUROPÉEN DE NORMALISATIONEUROPÄISCHES KOMITEE FÜR NORMUNGManagement Centre: rue de Stassart, 36
B-1050 Brussels© 2001 CENAll rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 12670:2001 ESIST EN 12670:2002

EN 12670:2001 (E)2ContentspageForeword.3Introduction.41Scope.52Terminology of Natural Stone.52.1Geological terms.52.2Quarrying terms.272.3Processing terms.292.4Products and installation terms.323Scientific Classifications.353.1Geological Time Scale (Informative).353.2Scientific Classification Charts.363.2.1Igneous Rocks Classification Charts.363.2.2Sedimentary Rocks Classification Charts.423.2.3Metamorphic Rocks Classification Chart.46Annex A (informative)
Alphabetic Index.47Bibliography.53SIST EN 12670:2002

EN 12670:2001 (E)3ForewordThis European Standard has been prepared by Technical Committee CEN/TC 246 "Natural Stone",the secretariat of which is held by UNI.This European Standard shall be given the status of a national standard, either by publication of anidentical text or by endorsement, at the latest by June 2002, and conflicting national standards shall bewithdrawn at the latest by June 2002.This draft standard is one of a series of standards for natural stone products including denomination,test methods and product standards.Annexes A and B are informative.According to the CEN/CENELEC Internal Regulations, the national standards organizations of thefollowing countries are bound to implement this European Standard: Austria, Belgium, CzechRepublic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg,Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and the United Kingdom.SIST EN 12670:2002

EN 12670:2001 (E)4IntroductionThe term Natural Stone groups several rock types with marked geological differences. The extractionelaboration and commerce of Natural Stone have set a very particular vocabulary. Many of theseterms have been taken from the popular or quarrymen language, which sometimes is far fromscientific definitions; this often results in a great deal of confusion.This standard establishes the terminological bases for geological and petrologic definitions of NaturalStone and its classification. References to definitions of natural stone products, defined in otherEuropean Standards, are provided when necessary. It also incorporates most of the popular orcommercial terminology.The terminology covers the fields of geology, mining, processing, marketing and products of NaturalStone. The included scientific classifications allows to set the scientific name of the stone varieties.SIST EN 12670:2002

EN 12670:2001 (E)51 ScopeThis European Standard defines the recommended terminology covering scientific, and technicalterms, test methods, products, and the classification of Natural Stones.2 Terminology of Natural StoneNOTE
the purposes of this European Standard the following abbreviations apply:e.g.
for example (Latin exempli gratia);i.e.
that is (Latin id est).2.1 Geological terms2.1.1 accessory minerals: Rock-forming minerals that occur in such small amounts that they arenot included in the classification of the rock.NOTE
Accessory minerals can be used to state precisely the name of the rock, e.g. biotite granite. (See also EN12440).2.1.2 acid rock: Igneous rock that contains more than 65 % of silica.2.1.3 actinolite: Ca-Mg-Fe-amphibole. See amphibole formula.2.1.4 agate: Cryptocrystalline variety of silica, showing a variegated banded structure and waxyluster.2.1.5 agglomerate: Extrusive pyroclastic rock of consolidated or unconsolidated coarse volcanicfragments (with diameters greater than 64 mm), in which rounded pyroclasts predominate.2.1.6 alabaster: Fine grained, compact variety of gypsum, usually white or pale coloured andtranslucent.2.1.7 albite: Sodium plagioclase, formula Na Al Si3 O8 See plagioclase.2.1.8 alkali feldspar: The alkali-rich feldspars microcline, orthoclase, sanidine, albite, with less than5% anorthite. See feldspar and plagioclase.2.1.9 allochems: One of the several varieties of discrete and organized carbonate aggregates thatserve as the coarser framework grains in most mechanically deposited limestones. Importantallochems include: silt, sand, gravelsize intraclasts ooids; pellets; lumps and fossils or fossilfragments.2.1.10 allotriomorphic; anhedral; xenomorphic:
Term applied to minerals which show in thinsections no characteristic or rational faces, suggested by its crystalline structure.2.1.11 alteration: Changes of the mineralogical composition of a rock brought about by physical,chemical or biological means, including actions of hydrothermal solutions and weatheringprocesses. Differs from metamorphism in being milder, more localized and not restricted tohigh temperatures.2.1.12 alumina; corundum: A mineral, formula Al2O3. Used in fine polishing.2.1.13 amorphous: Mineral that does not have a crystalline structure.2.1.14 amphibole: Family of dark ferromagnesian silicate minerals, general formulaA2-3B5(Si,Al)8O22(OH)2, where A= Mg, Fe2+, Ca, Na; B=Mg, Fe2+, Fe3+, Al.2.1.15 amphibolite: Metamorphic rock consisting mainly of amphibole and plagioclase. See amygdaloidal: Fabric of volcanic rocks where vesicles are present, which are full or partiallyfilled with secondary minerals.2.1.17 analcime: A mineral Na AlSi2O6 H2O of the zeolite group, which can occur in basalts. SeeSIST EN 12670:2002

EN 12670:2001 (E)6also zeolite, secondary minerals.2.1.18 anhedral: See allotriomorphic.2.1.19 anisotropy: Property of some minerals and rocks of having different behaviour in differentdirections. i.e. hardness in kyanite, thermal expansion in calcite, flexural resistance in slate.2.1.20 andalusite: Mineral Al2SiO5 polymorphous with sillimanite and kyanite.2.1.21 andesite: Volcanic rock composed mainly of plagioclase (oligoclase-andesine) and one ormore of the dark minerals amphibole, pyroxene, and biotite.2.1.22 anhydrite: Sedimentary evaporitic mineral, formula CaSO4.2.1.23 ankerite: Mineral of dolomite group with calcium and iron.2.1.24 anorthite: Calcic plagioclase, Ca Al2Si2O8. See plagioclase.2.1.25 anorthoclase: Sodium-rich mineral of the alkali feldspar group, formula (Na,K)AlSi3O8. Itscomposition, in term of the mole fraction of the orthoclase component (or) and the albitecomponent (ab) is or40ab60 to or10ab90. See feldspar, microcline, plagioclase, orthoclase.2.1.26 anorthosite: Plutonic rock mainly composed of plagioclase and little or no dark minerals. See3. antiperthite: Feldspar containing intergrowth lamellae of orthoclase in albite. See alsofeldspar and perthite.2.1.28 apatite: Group of minerals, formula Ca5(PO4,CO3)3(F,OH,Cl).2.1.29 aplite: Fine grained dyke rock of granitic composition.2.1.30 aragonite: Mineral, polymorphous with calcite, formula CaCO3.2.1.31 arenite: Consolidated sedimentary rock
mainly composed of sand-size detrital fragments ormineral grains, usually the term is used with a prefix that refers to its composition or genesis,e.g. quartzarenite. See also argillite: Consolidated sedimentary rock mainly composed wholly of detrital clay-size particlesor clay minerals.2.1.33 arkose: Sedimentary detrital rock with less than 75 % quartz and a high content of feldspargrains. See augen fabric; ocellar fabric: Fabric in some rocks, usually metamorphic, consisting ofellipsoidal or lens-shaped porphyroblasts, crystals, or fragments, rounded and enveloped bythe foliation, resembling eyes (augen) in a cross section.2.1.35 augite (clinopyroxenes): Mineral of the pyroxene group (clinopiroxenes), general formula(Ca,Na) (Mg,Fe2+,Al) (Si,Al) 2O62.1.36 banded: Rock having alternating nearly parallel layers that differ in colour, fabric or mineralcomposition, and because of that it shows alternating bands in a cross section.2.1.37 basalt (basanite): a) Scientifically: volcanic rock consisting essentially of plagioclase (labradorite-anorthite) andpyroxene and includes a fine grained to dense fabric (See b) Commercially: basalt is a natural stone as per the scientific definition of basalt and other rockssuch as basalt, picrites, diabases, dolerites and microgabbros.2.1.38 basic: Igneous rock with more than 45 % and less than 52 % of silice.2.1.39 bedding plane: a) A planar or nearly planar surface that visibly separates the individual beds, layers or strata,especially in sedimentary rocks.SIST EN 12670:2002

EN 12670:2001 (E)7 b) Any surface, even when conspicuously bent or deformed by folding.2.1.40 bioclastic rock: Sedimentary rock consisting of fragments and broken remains of organisms;e.g. limestone composed of shell fragments.2.1.41 biotite: Black rock-forming mineral of the mica group, formula K(Mg,Fe2+)3(Al,Fe3+) Si3O10(OH) blasto: Prefix used to describe the metamorphic rock fabrics denoting the presence ofresidual crystals or pre-existing fabric modified by metamorphism, but still recognized; e.g.blastogranular, blastomylonitic.2.1.43 breccia: a) A coarse-grained clastic sedimentary rock composed by angular rock fragments held togetherby a mineral cement or in a fine grained matrix. b) Rock consisting of highly angular coarse fragments, of whatever origin, for example, volcanicbreccia (explosive origin), fault breccia (tectonic crushing origin), intraclastic breccia (sedimentaryorigin).2.1.44 Buntsandstein: The lower part of Triassic Period. See calcarenite: Limestone consisting predominantly of recycled detrital calcite grains of sandsize.2.1.46 calcareous: Containing calcium carbonate.2.1.47 calcilutite: Limestone consisting predominantly of detrital calcite grains or fragments of silt orclay size.2.1.48 calcirudite: Limestone consisting predominantly of detrital calcite grains or fragments largerthan sand size. See rudite.2.1.49 calcisiltite: Limestone consisting predominantly of detrital calcite grains or fragments of siltsize.2.1.50 calcite: Mineral, very common in some sedimentary and metamorphic rocks, formula CaCO3;trimorphous with aragonite and vaterite.2.1.51 calcitic dolomite: Carbonate rock which 50 % to 89 % of the mineral dolomite. (See also3.2.2.2).2.1.52 calcitic marble: a marble containing more than 90 % of calcite.2.1.53 calc-silicate marble: Marble with calcium and partially magnesium silicate minerals. Seemarble, ophicalcite, calc-schist; carbonate mica-schist: Schist with carbonate minerals, in a lesser amount thana marble. See schist, Cambrian: The oldest system and period into which the Palaeozoic is divided. See carbonate : Mineral containing CO32-; calcite, dolomite, magnesite, and siderite are frequentrock-forming carbonate minerals.2.1.57 carbonate rock: Rock consisting chiefly of carbonate minerals, especially a sedimentaryrock; limestone, dolomite, and carbonatite are examples of carbonate rocks. See Carboniferous: Period and system of the Palaeozoic. See cataclastic: Pertaining to the structure and texture produced in a rock by severe mechanicalstress during dynamic metamorphism; bending, breaking, and fragmentation of the mineralgrains are characteristic features; also said of the rocks exhibiting such structure. (See alsobreccia).2.1.60 cement: Mineral materia, usually chemically precipitated, that occurs in the spaces among theindividual grains of a consolidated sedimentary rock, thereby binding the grains together as arigid mass; silica, carbonates and iron oxides are common cements.SIST EN 12670:2002

EN 12670:2001 (E)82.1.61 Cenozoic: Era of geologic time. See chalcedony: Cryptocrystalline commonly fibrous variety of silica.2.1.63 chalcopyrite: Mineral formula CuFeS2.2.1.64 chalk: Soft fine-grained limestone, consisting almost wholly of calcitic remains frommicroorganisms, usually white.2.1.65 charnockite: Orthopyroxene-bearing. Member of granite family.2.1.66 chert: Hard, compact and dense sedimentary rock, consisting dominantly of cryptocrystallineand/or amorphous silica; flint is a variety of chert.2.1.67 chlorite: Group of clay minerals, some of them of green colour, general formula (Mg, Fe2+,Fe3+)6 AlSi3O10(OH) chloritoid: Micaceous mineral, formula Fe2Al4Si2O10(OH) chromite: Mineral formula (Fe,Mg)(Cr,Al)2O4.2.1.70 cipollino marble: Calc silicate marble with band coloured structure, consisting in layers ofcalcite or dolomite grains mixed with variable quantities of silicate minerals.2.1.71 clast: mineral or rock fragment composing clastic sedimentary rocks.2.1.72 clastic: Pertaining to a rock or sediment composed principally of broken fragments that arederived from preexisting minerals, rocks or organic structures and that have been transportedsome distance from its original place.2.1.73 clay: Loose, extremely fine grained sediment or soft rock composed of particles withdiameters less than 0,002 mm, mainly of clay minerals and other minerals, especially quartz,feldspars, and carbonates (see clay minerals: Group of minerals, essentially
hydrous silicates of aluminium with a layeredcrystalline structure; iron, magnesium, potassium, and other cations are also present in theirformula; the most common clay minerals belong to illite, montmorillonite, and kaolinite mineralsubgroups.2.1.75 clay slate; shale: A weakly metamorphosed claystone with intermediate character between aclaystone and a true slate.2.1.76 claystone: A rock with more than 67 % claysized minerals.2.1.77 cleavage: a) Tendency of a rock to split along closely spaced planar surfaces, originated by recrystallizationand strain during metamorphism and tectonic deformation; the type of rock, strain intensity, andmetamorphic grade, control the type of cleavage developed; see slaty cleavage, crenulationcleavage, schistosity, and rough cleavage; b) The splitting of a mineral along its crystallographic planes, thus reflecting crystal structure.2.1.78 columnar: A structure of some volcanic rocks, such as basalt, consisting of parallel, prismaticcolumns, polygonal in cross section, nearly perpendicular to the top and the bottom of theflow.2.1.79 comb layering; Willow-Lake layering: A fabric of igneous rocks consisting of bands ofelongated crystals with nearly vertical mineral-elongation relative to the border of the bands.2.1.80 concretion: A collective term applied loosely to various primary and secondary segregationsof diverse origin, including irregular nodules, spherulites, crystalline aggregates, geodes,septarias and related bodies.2.1.81 conglomerate: Coarse-grained sedimentary rock composed of rounded to subangularfragments (pebbles, cobbles, boulders), set in a fine-grained matrix of sand or clay, andcommonly cemented.SIST EN 12670:2002

EN 12670:2001 (E)92.1.82 consertal: Fabric of rocks showing toothed border lines between two minerals.2.1.83 contact (between grains): Mode of relation between grains of rock-forming minerals; i.e. bypoints, by lines, within the matrix.2.1.84 coral rock: Coral reef limestone.2.1.85 corona: A fabric of igneous rocks where minerals are surrounded by a seam of one or moreother minerals; particular examples are the rapakivi fabric and kelyphitic rims.2.1.86 cordierite: A silicate mineral, common in some metamorphic and magmatic rocks, formula(Mg,Fe)2 Al4Si5O18.2.1.87 Cretaceous: The youngest of the periods and systems included in the mesozoic. (See 3.1).2.1.88 cross-bedding: Cross-stratification with thick individual beds2.1.89 crossed twinning: Lamellae of mineral twins after two laws making in thin sections a grid asseen in microcline.2.1.90 cryptocrystalline: Composed of crystal so fine that they cannot be recognized even underpolarizing microscope.2.1.91 crystal zoning: A fabric of igneous rocks with concentric layers in the minerals made byinclusions or variations in chemical composition e.g. in plagioclases.2.1.92 dacite: Volcanic rock with quartz, plagioclase, alkali feldspar, and often dark components.(See dark mineral; mafic mineral: In thin section dark-coloured rock-forming minerals, e.g. olivine,pyroxenes, amphiboles and biotite.2.1.94 decussate: Fabric of granoblastic metamorphic rocks in which the crystals tend to beelongated or prismatic and randomly oriented.2.1.95 dedolomitization: The change of dolomite into calcite and periclase (brucite).2.1.96 deformation fabric; tectonic fabric: A rock fabric resulting from deformation, as lineations,cleavages, schistosities, folds, preferred orientations of crystals etc. (See fabric).2.1.97 devitrification:The process by which glassy parts of rocks change into crystalline minerals.2.1.98 Devonian: A system of the Paleozoic Erathem above the Silurian and below theCarboniferous. See also diabase: Altered basaltic rocks like dolerites.2.1.100 diagenesis: Process of mineralogical changes in sediments after deposition which result in aconsolidated rock.2.1.101 diorite: Plutonic rock mainly composed of plagioclase (oligoclase-andesine), hornblende,and/or biotite.2.1.102 dip: Inclination of a bed to the horizontal; the dip is at a right angle to the strike.2.1.103 dolerite: Igneous rock with basaltic composition, commonly with ophitic fabric, ocurring indykes. See also diabase.2.1.104 dolomite: 1) The mineral CaMg(CO3)2, commonly with some Fe replacing Mg (ankerite). 2) Carbonate rock with high percentage (90 % to 100 %) of the mineral dolomite. (See dolomitic limestone: Carbonate rock with a certain percentage (10 % to 49 %) of the mineraldolomite. (See dolomitic marble; magnesian marble: a marble containing dolomite more than 90 %dolomite.SIST EN 12670:2002

EN 12670:2001 (E)102.1.107 dyke (or dike): A tabular or nearly tabular body of igneous rock that cuts across thegeological structure of other rocks.2.1.108 eclogite:
Metamorphic rock consisting essentially of garnet and sodic pyroxene (omphacite).2.1.109 elongate fabric: Fabric of granoblastic metamorphic rocks in which the crystals tend to beelongated with preferred orientation.2.1.110 epidote: A mineral Ca2(Fe,Al)Al2[O(OH)(SiO4)(Si2O7)] common in some metamorphic rocks oras alteration product.2.1.111 equigranular fabric: Rock containing crystals of a similar size.2.1.112 erathem: Chronostratigraphic unit. An erathem consists of several adjacent systems.2.1.113 essential minerals; main minerals: Those minerals existing in a rock that are used for itsclassification in main petrographic families or classes; see quartz, alkali feldspar, plagioclase,feldspathoids. (See also EN 12407).2.1.114 essexite: Plutonic rock composed essentially of plagioclase, alkali feldspar, feldspathoids e.g.nepheline, and dark minerals.2.1.115 eucrystalline; eucrystallized: Well crystallized igneous rocks.2.1.116 euhedral; idiomorphic: A mineral grain in an igneous rock which is bounded entirely by itscrystal faces.2.1.117 exfoliation: The process by which concentric or parallel scales of rock are spalled from thesurface of a large rock mass.2.1.118 extrusive rocks; volcanic rocks: Igneous rocks that come to the surface of the earth in amolten condition.2.1.119 fabric: Spatial arrangement and geometrical relationships of the rock elements, as observedin hand specimen or by optical microscope.2.1.120 fabric, depositional: A fabric resulting from deposition of sediments or gravity differentiationof igneous rocks.2.1.121 fabric element: Rock component that acts as a unit in deformation.2.1.122 fabric, growth: Fabric grown without stress and movement.2.1.123 facies: General appearance or nature of a rock mass, differentiating such unit from adjacentor associated units.2.1.124 fault: A fracture with displacement of the sides.2.1.125 feldspar: Group of silicate minerals with the chemical composition KAlSi3O8 (orthoclase,microcline), NaAlSi3O8 (albite), CaAl2Si2O8 (anorthite) with certain miscibility of thesecomponents; see anorthite, microcline, orthoclase, sanidine, plagioclase.2.1.126 feldspathic: Containing feldspar in a considerable amount.2.1.127 feldspathic sandstone; subarkose: A sandstone with less feldspar than an arkose (lessthan 15 % matrix, between 75 % and 95 % quartz, more feldspar, and less fragments ofrocks). (See fels: A suffix added to the name of a a mineral, indicating a metamorphic rock with more than80 % of that mineral, e.g. albite-fels, quartz-fels=quartzite. (See felsic: Containing feldspar, feldspathoids and other light silicates like quartz.2.1.130 ferruginous: Containing iron.2.1.131 fissile bedding: Bedding with laminae less than 2 mm in thickness.2.1.132 fissility: The property of splitting easily along closely spaced parallel planes.SIST EN 12670:2002

EN 12670:2001 (E)112.1.133 fissure: A visible crack or fracture in the rocks.2.1.134 flint: Variety of chert.2.1.135 flow fabric: Fluidal fabric in the groundmass of rocks shown by a wavy or swirling pattern ofthe constituent minerals.2.1.136 fluorite: A mineral, formula CaF2.2.1.137 foidite (feldspathoidite): A volcanic rock with high percentage (more than 60 %) of foids.(See foidolite (feldspathoidolite): A plutonic rock with high percentage (more than 60 %) of foids.(See foids (feldspathoids): Minerals similar to the feldspars but with less silica content e.g.leucite, nepheline, sodalite.2.1.140 fold: A bend in formerly planar or tabular rock bodies.2.1.141 foliation: Planar arrangement of components like minerals in any type of rock, especially theplanar structure that results from flattening, segregation and other processes undergone bythe grains in a metamorphic rock. (See also cleavage).2.1.142 formation: The basic stratigraphic unit identified by lithic characteristics and fossils.2.1.143 fossil: The remains or marks of animals or plants in sedimentary rocks.2.1.144 gabbro: A coarsed grained plutonic rock consisting of plagioclase (labradorite-anorthite),clinopyroxene, and other minerals like orthopyroxene, and olivine. (See garnet: A group of minerals of formula x3y2 (SiO4)3 where x=Ca,Mg,Fe2+,Mn2+ andy=Al,Fe3+,Mn3+,V3+,Cr.2.1.146 geode: Globular bodies in sediments often containing fossils and crystals.2.1.147 geological structure: a) A macroscopic feature of a rock mass or rock unit, generally seen best in the outcrop rather thanin hand specimen, e.g. columnar structure, blocky fracture, platy parting, bedding. b) The general disposition, attitude, arrangement or relative positions of the rock units of a regionor area, resulting from such geological processes as sedimentation, faulting, folding, igneousintrusion, etc.2.1.148 glass: Non-crystallized product of the rapid cooling of a magma.2.1.149 glauconite: A green mineral closely related to biotite and essentially an hydrous potassiumiron aluminium silicate in sedimentary rocks, formula (K,Na)(Al,Fe3+,Mg)2(Al,Si)4O10(OH) gneiss: A metamorphic rock mainly consisting of quartz, feldspar and mica, in which bandsrich in granular minerals such as feldspar and quartz, alternate with bands of planar mineralslike mica. Might derive from an igneous rock (orthogneiss) or from a sedimentary rock(paragneiss). (See leptite and 3.2.3).2.1.151 gneissose, gneissic fabric: Fabric in metamorphic rocks in which bands rich in granularminerals alternate with bands of planar minerals.2.1.152 goethite: A mineral (-FeOIOH).2.1.153 graded bedding: Stratification in which each stratum shows a gradation in grain size fromcoarse to fine.2.1.154 grain: Particles of a rock e.g. the crystals in a granite.2.1.155 grain size: The predominant diameter of particles in a rock as observed.2.1.156 granite:SIST EN 12670:2002

EN 12670:2001 (E)12 a) Scientifically: Plutonic rock with alkali feldspar, quartz, little quantities of plagioclase, mica, andother minerals. (See b) Commercially: Compact and polishable natural stone, used in decoration and building, mainlyconsisting of minerals with a hardness between 5 and 7 on the Mohs scale, such as quartz andfeldspar, e.g. granite as per the scientific definition, other plutonic rocks, volcanic rocks withporphyritic structure, metamorphic rocks with mineralogical composition similar to granitoids suchas gneiss, and limestone in some regions of Europe. (See hardness scale).2.1.157 granite, black: A commercial term for black or dark coloured igneous rocks. (See gabbro).2.1.158 granoblastic: Fabric of metamorphic rocks in which the grains are of nearly equal size.2.1.159 granodiorite: A plutonic rock resembling granite but with less alkali feldspar and with moreplagioclase. (See granofelsose: Fabric of granoblastic metamorphic rocks with little or no foliation or lineation.2.1.161 granophyric: A variety of graphic fabric with more or less intergrowth of alkali feldspar andquartz e.g. around plagioclases.2.1.162 granular: Term applied to rocks with nearly equal grains.2.1.163 granulite: A metamorphic rock with K-feldspar, quartz and garnet and/or different otherminerals and no primary muscovite.2.1.164 graphic: A fabric of igneous rocks resulting from a regular intergrowth of two minerals andshowing graphic patterns in sections, e.g. in graphic granite.2.1.165 graphite: Mineral, one of the two natural occuring forms of crystalline carbon, the other beingdiamond.2.1.166 greywacke: A sandstone with abundant (more than 15 %) matrix. (See greenschist: A schistose metamorphic rock with albite whose green colour is due to thepresence of chlorite, epidote, or actinolite. (See greenstone: An altered igneous rock with chlorite, hornblende, epidote, and withcomparatively low silica content.2.1.169 grit: Sedimentary rock with coarse and angular grains.2.1.170 groundmass; matrix: The material between the grains or inclusions in a rock.2.1.171 growth fabric: Crystal arrangement determined by more or less free growth from a plane or acentre.2.1.172 gypsum: A mineral CaSO4.2H2O also called selenite; the dense varieties are called alabaster.2.1.173 habit: The characteristic crystal form or combination of forms of a mineral, includingcharacteristic irregularities; i.e. idiomorphic.2.1.174 heavy minerals: Accessory minerals with a density greater than 2,9 g/cm3.2.1.175 hematite: A mineral, alpha-Fe2O3.2.1.176 heteroblastic fabric: Term referring to metamorphic rocks composed of crystals with a rangeof sizes.2.

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