SIST EN 12407:2019

SLOVENSKI STANDARD
oSIST prEN 12407:2016
01-oktober-2016
Preskušanje naravnega kamna - Petrografska preiskava
Natural stone test methods - Petrographic examination
Prüfverfahren für Naturstein - Petrographische Prüfung
Méthodes d'essai pour pierres naturelles - Examen pétrographique
Ta slovenski standard je istoveten z: prEN 12407
ICS:
73.020 Rudarstvo in kamnolomsko Mining and quarrying
izkopavanje
91.100.15 Mineralni materiali in izdelki Mineral materials and
products
oSIST prEN 12407:2016 en,fr,de
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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oSIST prEN 12407:2016


DRAFT
EUROPEAN STANDARD
prEN 12407
NORME EUROPÉENNE

EUROPÄISCHE NORM

August 2016
ICS 73.020; 91.100.15 Will supersede EN 12407:2007
English Version

Natural stone test methods - Petrographic examination
Méthodes d'essai de pierres naturelles - Examen Prüfverfahren für Naturstein - Petrographische
pétrographique Prüfung
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 246.

If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,
Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.

Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.


EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels
© 2016 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 12407:2016 E
worldwide for CEN national Members.

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Contents Page
European foreword . 3
Introduction . 4
1 Scope . 5
2 Normative references . 5
3 Principle . 5
4 Symbols . 5
5 Apparatus . 5
6 Preparation of thin and polished sections . 6
6.1 General . 6
6.2 Staining . 7
6.2.1 Feldspar staining . 7
6.2.2 Carbonate staining . 7
7 Macroscopic description . 7
7.1 General . 7
8 Microscopic description . 7
9 Petrographic classification . 9
10 Test report . 9
Annex A (informative) Preparation of thin sections . 11
Annex B (informative) Staining preparation and procedure of thin sections. 12
Annex C (informative) Principe and procedure of point counting . 14
Annex D (informative) Template for the petrographic description of rocks . 15
Bibliography . 20

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European foreword
This document (prEN 12407:2016) has been prepared by Technical Committee CEN/TC 246 “Natural
stones”, the secretariat of which is held by AENOR.
This document is currently submitted to the CEN Enquiry.
This document will supersede EN 12407:2007.
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Introduction
A petrographic description of natural stones is important not only for the purposes of petrographic
classification but also in order to highlight features affecting its chemical, physical and mechanical
behaviour. In the same way the determination of the stone’s origin could be necessary (e.g. in the case
of restoration of historical monuments). It is therefore essential to characterize the natural stones for
their mineral components and of their fabric and structure but also in terms of any features as: colour,
presence of veins, of fossils, of discontinuities, etc.
To ensure that the petrographic classification is objective, it is essential that the characterization of the
material is, as far as possible, quantitative.
The interpretation of the results obtained from the petrographic examination of natural stone should
include evidences of a possible relationship between petrographic features and technical properties
(pores/cleavages/ schistosity with water absorption/ gelivity/ flexure resistances etc.).
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1 Scope
This European Standard specifies methods for making technical petrographic descriptions of natural
stone, except for roofing slates. For this product, the method for the petrographic examination is
defined in EN 12326–2. Although chemical and physical methods of analysis are required for
petrographic classification of some stone types, these methods will not be described in this standard.
2 Normative references
The following documents, in whole or in part, are normatively referenced in this document and are
indispensable for its application. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 12670, Natural stone — Terminology
EN 12440, Natural stone — Denomination criteria
3 Principle
A macroscopic description of the sample is undertaken at first. The macroscopic description may
involve a visual inspection aided by a hand lens or a stereoscopic microscope. Then one or more thin
sections prepared from the sample are examined using an optical polarized transmitted light
microscope in order to give a microscopic description and modal analysis (volume proportions of
mineral phases) of the sample; where appropriate an additional polished section shall be prepared.
Modal analysis is the most accurate determination of quantitative mineralogical composition of natural
stones. It attributes to each mineral phase a certain percentage (vol.%). Modal analysis is obtained by
2
point counting following a standard procedure on thin sections (44 × 28 mm ) or using Shvetsov’s
diagrams (or any other similar diagrams commonly used by petrographers).This is a common method
to determine the mode (volume percentage of each mineral) in which the identity of the mineral phase,
in a series of equally spaced points on a grid, is determined and recorded.
4 Symbols
vol.%  unit of the volume percentage of the mineral phase present in the sample.
5 Apparatus
5.1 Hand lens or stereoscopic microscope (if required).
5.2 Water cooled rock cutter equipped with a continuous rim and sliding guide.
5.3 Automatic grinding machine or manual grinding machine with a cast-iron lapidary.
5.4 Electrical heating plate.
5.5 Bonding press.
5.6 Extractor hood.
5.7 Glass plate c. 300 mm × 400 mm × 10 mm.
5.8 Soft bristle brush.
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5.9 Ultrasonic tank.
5.10 Polarized transmitted light optical microscope.
5.11 Point counter and image analysis system (if required).
5.12 Reactives and products: emery with grain size varied (30 µ to 10 µ), Epoxy resin, Canada Balsam,
Supporting glass (28 mm x48 mm x1,8 mm), cover glass (24 mm x32 mm), diamond disks, xylene and
ethanol, amaranth, sodium cobaltinitrite, hydrofluoric acid, hydrochloric acid, sulphosodic alizarin.
To facilitate the identification of some minerals with similar colours or optical properties it might be
necessary in many cases to use different techniques such as: selective mineral staining methods, optical
cathodoluminescence, XRD, SEM-EDS or WDS microprobe. If required, these methods should be
clearly stated in the working order referring to widely-referenced manuals, but taking into account that
such additional techniques are not part of the petrographic analysis described in this standard.
6 Preparation of thin and polished sections
6.1 General
Sampling is not responsibility of the test laboratory except where specially requested.
The dimensions of the sample shall be large enough to be representative of the petrographic
characteristics of the stone being examined.
One or more thin sections are then prepared.
A thin section is a portion of material mounted on a slide and mechanically reduced to a thin sheet
measuring 0,030 ± 0,005 mm in thickness, and normally protected by a slide cover. For special
purposes (observations under reflected light microscope for the determination of opaque minerals or
microprobe analysis) polished thin sections shall be prepared. Polished sections have one side polished
with alumina polishing paste (5 μm to 12 μm grade) and diamond paste (6 μm, 3 μm and 1 μm). The
polished face is left uncovered.
The section normally measures about 44 mm × 28 mm, but in the case of coarser grain size stones,
larger dimensions may be used (e.g. 75 mm × 50 mm) or several sections of normal dimensions can be
prepared. If the rock texture is anisotropic it is necessary to prepare at least two sections with different
orientation with respect to the anisotropy (e.g. parallel and perpendicular to anisotropy planes).
Preparation of thick sections
The sample shall be sufficiently coherent so as not to disintegrate when cut. If the stone is brittle or
fragile, it will be necessary to strengthen it by means of impregnation, preferably in a vacuum, with
resins with an index of refraction approximately 1,54 (e.g. epoxy resins).
Using the rock cutter several small blocks are cut of 44 mm × 32 mm and 3 to 4 mm thick. In case of
porous samples pores are filled with Canada balsam (or any synthetic resin with approximately
equivalent refractive index), heated on the plate to approximately 100 °C and then cooled.
Blocks are then successfully ground using diamond discs between 1 and 2 min depending on the type
and hardness of their constituent minerals.
Preparation of thin sections
The detailed description of preparation of thin sections is given in Annex A (informative).
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6.2 Staining
6.2.1 Feldspar staining
The detailed description of feldspar staining preparation and procedure is given in Annex B
(informative).
6.2.2 Carbonate staining
If samples are suspected of containing carbonates, their selective staining can be carried out. Samples
are etched with a HCl solution 1:20 and then immersed in a alizarine solution during 3 min. Then
samples are washed with water and are left to dry in open air. Calcite will then stain with a dark red
colour, dolomite will maintain its original colour and other carbonates will be stained between rose and
violet colour depending on the case. It is possible to discriminate other carbonates than calcite using
other chemical attacks, but this is not frequent.
7 Macroscopic description
7.1 General
Macroscopic description shall be carried out on a fresh broken samples and, if considered necessary, on
polished samples.
The following observations shall be included in the macroscopic description:
7.2 The general colour or range of colours of the hand specimen. The colour can be estimated by
visual impression or defined using a colour reference chart (Rock Colour Chart is recommended).
7.3 Rock structure (joints, bedding, stylolites, etc).
7.4 Grain size (e.g. coarse, medium or fine).
7.5 Open and refilled macroscopic cracks, pores and cavities (when relevant).
7.6 Evidence of weathering and alteration: staining by sulphide alteration, diffusion of iron
hydroxides, alteration of feldspars etc. (when relevant).
7.7 Presence of macrofossils (when relevant).
7.8 Presence of xenolithic and/or autolithic inclusions (when relevant).
8 Microscopic description
The following observations shall be included in the microscopic description:
8.1 Fabric.
8.2 Constituents:
8.2.1 Minerals/Grains.
For the determination of the opaque minerals polished sections should be used.
For each mineral or grain identified, the characteristics listed below shall be specified (when relevant).
8.2.1.1 Percentage by volume (vol.%), specifying the method used (e.g. estimate, point counter).
The detailed principle and procedure are given in Annex C (informative).
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8.2.1.2 Dimensions: mean value and range of variation (if necessary for the groundmass and also
for the larger crystals or grains). The range of sizes to be used will be: Very coarse (>10 mm), Coarse
(4 mm - 10 mm), Medium (1 mm - 4 mm), Fine (<1 mm). These values could not be used for clastic
rocks that require the widely-used Wentworth scale. In addition, the coarse-medium grain size limit for
igneous rocks is placed at 5 mm. Degree of sorting (in clastic rocks): very well sorted, well sorted,
moderately sorted, poorly sorted, very poorly sorted.
8.2.1.3 Habit (e.g. idiomorphic, anhedral).
8.2.1.4 Shape (e.g. isometric, anisometric, flattened, elongated). Detrital grains in sedimentary
rocks shall be described in terms of sphericity and roundness.
NOTE For marble see also EN 16306 Natural stone test methods — Determination of resistance of marble to
thermal and moisture cycles.
8.2.1.5 Boundaries (e.g. straight, lobate, dentate).
8.2.1.6 Distribution (e.g. homogeneous, heterogeneous, in layers, in patches).
8.2.1.7 Orientation (e.g. isotropic, shape preferred orientation, dimensional preferred orientation,
isorientation of lamellar or tabular grains, isorientation of elongated, prismatic grains).
8.2.1.8 Evidence of weathering and alteration: staining by sulphide alteration, diffusion of iron
hydroxides, chloritization of biotite; sericization of feldspars, radioactive decay of minerals such as
zircon or allanite etc.
8.2.2 Groundmass.
8.2.2.1 In volcanic rocks mesostasis which can be glassy, ipocrystalline, microcrystalline,
devitrified.
8.2.2.2 In sedimentary rocks have to be distinguished matrix (microcrystalline pelitic, carbonatic or
silicic mud which includes grains when present, or fills the interstices) and cement (amorphous to
crystalline materials partially or completely filling cavities).
8.2.3 Organogenic remains: e.g. organic or replaced (pyrite, apatite etc.) organogenic remains.
8.3 Discontinuities:
8.3.1 Pores, microcavities (size, shape, relative abundance and filling material if present).
8.3.2 Cracks and open fractures.
8.3.2.1 Width (most frequent value, minimum and maximum).
8.3.2.2 Length (most frequent value, minimum and maximum).
8.3.2.3 Type (intergranular, intragranular, transgranular)
8.3.2.4 Orientation.
8.3.2.5 Distribution.
8.3.3 Filled fractures and veins.
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8.3.3.1 Width (most frequent value, minimum and maximum).
8.3.3.2 Length (most frequent value, minimum and maximum).
8.3.3.3 Type (intergranular, intragranular, transgranular).
8.3.3.4 Orientation.
8.3.3.5 Distribution.
8.3.3.6 Filling (extent, nature, structure).
8.3.3.7 Nature (e.g. stylolites, late veins).
8.4 Alterations:
8.4.1 Description of the minerals with alterations.
8.4.2 Alteration grade of the rock.
Templates for the petrographic description of the various types of rocks are given in EN 12670.
9 Petrographic classification
On the basis of the data generated from the macroscopic and microscopic examination relating to grain
size, fabric and mineralogical composition a petrographic classification shall be assigned to the stone
sample, using EN 12670 and fixing at least the rock group/family.
If the petrographic description provides insufficient data to assign a petrographic classification, further
testing may be necessary, namely chemical and minerochemical determinations.
10 Test report
The test report shall contain the following information:
a) unique identification number for the report;
b) number, title and date of issue of this European Standard;
c) name and address of the test laboratory and the address of where the examination was carried out
if different from the test laboratory;
d) name and address of the client;
e) it is t
...