BS/EN 12670-2019 pdf download.Natural stone – Terminology.
3.1.77
carbonate-silicate rock
metamorphic rock mainly composed of silicate minerals (including calcium-silicate minerals) and containing between 5 % vol. vol and 50 % vol. vol of carbonate minerals
3.1.78
Carboniferous
period and system of the Palaeozoic
Note ito entry: See Table 1.
3.1.79
cataclasite
fault rock which is cohesive with a poorly developed or absent schistosity. or which is incohesive, characterised by generally angular porphyroclasts and lithic fragments in a fIner-grained matrix of similar composition
Note 1 to entry: Generally, no preferred orientation of grains of individual fragments Is present as a result of the deformation. but fractures may have a preferred orientation. A foliation is not generated unless the fragments are drawn out or new minerals grow during the deformation. Plastic deformation may be present but is always subordinate to some combination of fracturing, rotation and frictional sliding of particles. Cataclasite may be subdivided according to the relative proportion of f1nergrained matrix into protocataclasite, mesocataclasite and ultracataclasite
3.1.80
cataclastic
pertaining to the structure and texture produced in a rock by severe mechanical stress during dynamic metamorphism; bending. breaking. and fragmentation 01 the mineral grains are characteristic teatures; also said of the rocks exhibiting such structure
Note 1 to entry: See breccla.
3.1.81
cement
mineral material, usually chemically precipitated during the rock compaction that occurs in the interstitial spaces among the individual grains of a sedimentary rock thereby binding the grains together as a rigid mass; silica, carbonates and iron oxides are common cements
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Cenozoic
youngest era of geologic time
3.1.88
chlorite Group
group of phyllosilicates, some of them of green colour, with general formula (Mg, Fe2. Fe3)o
A1S13010(OH)8
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chioritoid
micaceous mineral, the formula of which is Fe2Al4SizOio(OH)a
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chro mite
mineral, the formula of which is (Fe,Mg)(Cr.Al)204
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chronostratigraphic unit
stage or zone which, independent of facies, represents a layer of specific age
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cipollino marble
Impure marble with band coloured structure, consisting in layers of calcite or dolomite grains mixed with variable quantities of silicate minerals
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clast
mineral or rock fragment composing clastic sedimentary rocks
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cisural ian
oldest epoch of the Permian
Note ito entry: See Table 1.
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clastic
pertaining to a rock or sediment composed principally of broken fragments that are derived from pre existing minerals, rocks or organic structures and that have been transported some distance from its original place
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clay minerals
group of minerals, essentially hydrous silicates of aluminium with a layered crystalline structure; iron, magnesium, potassium, and other cations are also present in their formula; the most common of which belong to illite, montmorillonite, and kaolinite mineral subgroups
3.1.97
clay slate
shale
weakly metamorphosed clay stone with intermediate character between a clay stone and a true slate
3.1.98
clay
loose, extremely fine gra:ned sediment or soft rock composed of particles with diameters less than 0,002 mm, mainly of clay minerals and other minerals, especially quartz, feldspars. and carbonates
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clay stone
rock with more than 67 % vol. clay sized minerals
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cleavage
a) property of a rock to spLit along closely spaced planar surfaces (see slaty cleavage. crenulation cleavage, schistosity, and rough cleavage);
b) splitting of a mineral along its crystallographic planes, thus reflecting crystal structure
3.1.101
clinopyroxene
monoclinic pyroxene exhibiting non-parallel extinction
3.1.102
columnar
structure of some volcanic rocks, such as basalt, consisting of parallel, prismatic columns, polygonal in cross section, nearly perpendicular to the top and the bottom of the flow unit
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comb layering
fabric of igneous rocks consisting of bands of elongated crystals with nearly vertical mineral-elongation relative to the border of the bands
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contact (between grains)
mode of relation between grains of rock-forming minerals; i.e. by points, by lines, within the matrix
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coral rock
coral reef limestone
3.1.109
cordierite
silicate mineral, common in some metamorphic and rare in magmatic rocks, the formula of which is (Mg,Fe)2 Al4SiO18
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corona
fabric of igneous or metamorphic rocks where minerals are surrounded by a seam of one or more other minerals
Note I to entry: Particular examples are the rapakivi fabric and kelyphitic rims.
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Cretaccous
youngest of the periods! and systems included in the Mesozoic era/erathem
Note Ito entry: See Table 1.
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cross bedding
cross stratification with thick individual beds
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crossed twinning
lamellae of mineral twins after two laws making in thin sections a grid as seen in microcline
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cryptocrystalline
composed of crystals so fine that they cannot be recognized even under polarizing microscope
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crystal zoning
texture of Igneous crystals with concentric layers made by inclusions or variations in chemical composition e.g. in plagloclases.BS/EN 12670-2019 pdf download.

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