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CERTIFICATE OF ANALYSIS FOR CERTIFIED REFERENCE MATERIAL
AC18.10660
Description: Shale, Proterozoic, Mintaro Shale Formation, Mintaro, South Australia, Australia.
The material consists of shale rock sourced from an operating (Mintaro) quarry located approx.
110km north of the city of Adelaide in South Australia. This Proterozoic (~800 Ma) siliclastic
sedimentary rock is part of the Mintaro Shale Formation originally deposited in a quiet,
relatively deep-water marine (outer shelf) environment. The mineralogy consists of quartz
(35 %), biotite (16 %), dolomite (12 %), muscovite-sericite (12 %) and plagioclase (10 %) with
minor amounts of chlorite, kaolinite, and calcite.
AC18.10660 is available as 50 g units packed into glass, wide-mouth jars.
Intended use: For use in evaluating instrumental analytical methods for the chemical analysis
of lithological samples.
Certified and informational values derived from analytical methods of analysis are provided in
Tables 1 and 2, respectively.
Approving officer: Management of the interlaboratory certification program by Craig Hamlyn
(Technical Manager, OREAS).
Minimum sample size: To relate analytical determinations to the values in this certificate, a
minimum dry sample mass of 0.2 g should be used.
Storage and period of validity: The certification of AC18.10660 remains valid, within the
specified measurement uncertainties, until June 2029, provided the CRM is stored in a clean
and cool dry place away from direct sunlight. This certification is nullified if the CRM is any way
changed or contaminated.
Maintenance of Certified Values: OREAS will monitor this CRM over the period of its validity.
If substantive technical changes occur that affect the value assignment before the expiration
of this report, OREAS will notify the purchaser (using the contact’s email address on the Sales
Order).
COA-1919-AC18.10660-R0
BUP-70-10-01 Ver:2.1
22-Nov-2024
Table 1. Certified Values and their associated 95% Expanded Uncertainty.
Constituent Certified 95 % Expanded Constituent Certified 95 % Expanded
(wt.%) Value Uncertainty (ppm) Value Uncertainty
Al2O3 11.37 0.16 As 20.3 1.9
CaO 6.13 0.09 B 184 51
Fe2O3 5.48 0.07 Ba 345 15
K 2O 2.85 0.03 Be 2.09 0.45
LOI1000 10.54 0.31 Bi 1.02 0.23
MgO 5.94 0.10 Cd < 10 IND
MnO 0.0931 0.0032 Ce 62.3 3.5
Na2O 1.32 0.04 Co 13.4 1.4
P2O5 0.200 0.010 Cr 65 10
SiO2 55.46 0.69 Cs 6.94 0.72
TiO2 0.829 0.022 Cu 29.1 8.7
SI unit equivalents: ppm (parts per million; 1 x 10-6) ≡ mg/kg; Dy 4.96 0.53
wt.% (weight per cent) ≡ % (mass fraction). Er 2.83 0.29
IND = indeterminate (due to limited reading resolution of
the methods employed. For practical purposes the 95 % Eu 1.16 0.14
Expanded Uncertainty can be set between zero and a two Ga 15.8 1.6
times multiple of the upper bound/non-detect limit value). Gd 5.57 0.31
Ge 1.80 0.29
Ho 0.95 0.13
In < 0.2 IND
La 32.5 2.3
Li 58.2 2.4
Lu 0.37 0.09
Mo <1 IND
Nb 10.8 1.7
Nd 29.3 2.1
Ni 23.9 11.3
Pr 7.65 0.74
Rb 129.8 6.7
S 406 103
Sb <2 IND
Sc 11.60 0.68
Sm 5.94 0.84
Sn 3.88 1.28
Sr 121.9 7.4
Ta <5 IND
Tb 0.81 0.11
Te <1 IND
Th 13.44 0.94
Tl 0.51 0.21
Tm 0.406 0.039
U 2.41 0.28
V 89.1 6.8
W < 20 IND
Y 26.7 1.5
Yb 2.64 0.37
Zn 76.9 5.9
Zr 197 25
COA-1919-AC18.10660-R0 Page: 2 of 5
Table 2. Indicative Values for AC18.10660.
Constituent Unit Value Constituent Unit Value Constituent Unit Value
Ag ppm <5 F ppm 809 Pb ppm 20.4
Au ppm < 0.002 Hf ppm 5.56 Re ppm < 0.1
Br ppm < 0.5 Hg ppm <1 Se ppm <3
C wt.% 2.31 Ir ppm < 0.005 SG Unity 2.78
SI unit equivalents: ppm (parts per million; 1 x 10-6) ≡ mg/kg; wt.% (weight per cent) ≡ % (mass fraction). Note: the number of
significant figures reported is not a reflection of the level of certainty of stated values. They are instead an artefact of
OREAS’ in-house CRM-specific LIMS.
Table 3. Physical properties of AC18.10660.
Bulk Density (kg/m3) Moisture (wt.%) Munsell Notation‡ Munsell Colour‡
553 0.56 N7 Light Gray
‡
The Munsell Rock Colour Chart helps geologists and archaeologists communicate with colour more effectively
by cross-referencing ISCC-NBS colour names with unique Munsell alpha-numeric colour notations for rock colour
samples.
Commutability: AC18.10660 is sourced from naturally occurring rock and will display similar
behaviour to routine ‘field’ samples in the relevant measurement process. Commutability is not
an issue for this CRM.
Instructions for handling, correct use and safety: Fine powders pose a risk to eyes and lungs.
The use of safety glasses and dust masks are advised. Pre-homogenisation of the CRM prior
to subsampling and analysis is not necessary as there is no particle segregation under
transport [13]. After taking a subsample, users should replace the lid of the jar promptly and
securely to prevent accidental spills and airborne contamination. AC18.10660 contains a non-
hygroscopic matrix with an indicative value for moisture provided to enable users to check for
changes to stored material by determining moisture in the user’s laboratory and comparing the
result to the value in Table 3 in this certificate. The stability of the CRM in regard to oxidation
from the breakdown of sulphide minerals to sulphates is negligible given its low sulphur
concentration.
Certified values and their associated 95 % expanded uncertainties are reported according to
ISO/IEC Guide 98-3:2008 [6,16] and are shown in Table 1. These values are metrologically
traceable to the international measurement scale (SI) of mass with major elements expressed
in % (mass ratio) and minor elements expressed in mg/kg. In line with popular use, data are
expressed as the mass fraction in either weight percent (wt.%) or parts per million, 1 x 10-6
(ppm). They are the means of accepted laboratory means after outlier filtering and are the
present best estimate of the true value.
Indicative values shown in Table 2 are metrologically traceable to the international
measurement scale (SI) of mass and are expressed in % (mass ratio) or mg/kg. In line with
popular use, data are expressed as the mass fraction in either weight percent (wt.%) or parts
per million, 1 x 10-6 (ppm). Indicative values are present where interlaboratory consensus is
insufficient to meet OREAS’ criteria for certification. AC18.10660 was also tested by OREAS for
various physical properties. Table 3 presents these findings that should be used for
informational purposes only.
Sample Preparation and Analysis: AC18.10660 was crushed to a nominal 14 mm particle size
then dried to constant mass at 105 °C. The dry material then underwent multi-stage milling to
COA-1919-AC18.10660-R0 Page: 3 of 5
achieve a particle size of 100 % passing 30 µm. Homogenisation was accomplished using
OREAS’ novel processing technologies and the final product was packaged into 50 g units in
glass jars sealed with plastic lids.
Ten commercial analytical laboratories participated in the program to certify the elements
reported in Table 1. Full ICP-OES and MS elemental suites were analysed using a lithium borate
fusion. These same laboratories also undertook lithium borate fusion with X-ray fluorescence.
Instrumental neutron activation analysis (INAA) was also performed at one laboratory. The
results generated by these quantitative analytical methods were pooled for certification
purposes.
The INAA data was also used for homogeneity verification whereby 20 x 1 g subsamples were
analysed at Actlabs, Ancaster in Canada. These data comprised an Analysis of Variance
(ANOVA) using paired samples taken systematically from 10 different sampling intervals
(representative of the prepared batch) and were randomised prior to assigning sample
numbers. The duplicate samples enabled an ANOVA by comparison of within- and between-
unit variances across the 10 pairs to test:
• Null Hypothesis, H0: Between-unit variance is no greater than within-unit variance
(reject H0 if p-value < 0.05);
• Alternative Hypothesis, H1: Between-unit variance is greater than within-unit variance.
The INAA data was not filtered for outliers prior to the calculation of p-values and no significant
p-values were observed across the 35 reported elements. The Null Hypothesis is accepted
with no evidence of heterogeneity.
Document history:
Revision No. Date Changes applied
0 22 November, 2024
nd
First publication.
References
[1] Govett, G.J.S. (1983). Handbook of Exploration Geochemistry, Volume 2: Statistics and Data Analysis in
Geochemical Prospecting (Variations of accuracy and precision).
[2] Ingamells, C. O. and Switzer, P. (1973). A Proposed Sampling Constant for Use in Geochemical Analysis,
Talanta 20, 547-568.
[3] ISO Guide 30:2015. Terms and definitions used in connection with reference materials.
[4] ISO Guide 33401:2024-01. Reference materials – Contents of certificates, labels and accompanying
documentation.
[5] ISO Guide 33405:2024-05. Reference materials – Approaches for characterization and assessment
of homogeneity and stability.
[6] ISO Guide 98-3:2008. Guide to the expression of uncertainty in measurement (GUM:1995).
[7] ISO 16269:2014. Statistical interpretation of data – Part 6: Determination of statistical tolerance
intervals.
[8] ISO/TR 16476:2016, Reference Materials – Establishing and expressing metrological traceability of
quantity values assigned to reference materials.
[9] ISO 17025:2017, General requirements for the competence of testing and calibration laboratories.
[10] ISO 17034:2016. General requirements for the competence of reference material producers.
[11] Munsell Rock Color Book (2014). Rock-Color Chart Committee, Geological Society of America (GSA),
Minnesota (USA).
COA-1919-AC18.10660-R0 Page: 4 of 5
[12] OREAS-BUP-70-09-11: Statistical Analysis - OREAS Evaluation Method.
[13] OREAS-TN-04-1498: Stability under transport; an experimental study of OREAS CRMs.
[14] OREAS-TN-05-1674: Long-term storage stability; an experimental study of OREAS CRMs.
[15] Thompson, A.; Taylor, B.N. (2008); Guide for the Use of the International System of Units (SI); NIST
Special Publication 811; U.S. Government Printing Office: Washington, DC; available at:
https://physics.nist.gov/cuu/pdf/sp811.pdf (accessed 22 November 2024).
[16] Van der Veen A.M.H. et al. (2001). Uncertainty calculations in the certification of reference materials,
Accred Qual Assur 6: 290-294.
Appendix
The semi-quantitative XRD results for AC18.10660 shown in Table 4 below, were undertaken by
ALS Metallurgy in Balcatta, Western Australia. The results are normalised to 100 % and
represent the relative proportion of crystalline material. Totals greater or less than 100 % are
due to rounding errors. 'Clay mineral' appears to be mainly vermiculite, smectite, and
palygorskite. Some amorphous material may be present including traces of pyrrhotite and
magnetite.
Table 4. Indicative mineralogy based on semi-quantitative XRD analysis.
Mineral / Mineral Group % (mass ratio)
Clay mineral 4
Chlorite 8
Kandite group <1
Annite - biotite - phlogopite 16
Muscovite 12
Clinopyroxene <1
Plagioclase 10
K-feldspar 1
Quartz 34
Calcite 2
Dolomite - ankerite 12
Siderite <1
Magnesite and/or ilmenite <1
Apatite Group <1
Participating laboratories
1. Actlabs, Ancaster, Ontario, Canada
2. AGAT Laboratories, Calgary, Alberta, Canada
3. American Assay Laboratories, Sparks, Nevada, USA
4. ARGETEST Mineral Processing, Ankara, Central Anatolia, Turkey
5. Intertek, Cupang, Muntinlupa, Philippines
6. Intertek, Perth, WA, Australia
7. PT Intertek Utama Services, Jakarta Timur, DKI Jakarta, Indonesia
8. SGS Canada Inc., Vancouver, BC, Canada
9. Shiva Analyticals Ltd, Bangalore North, Karnataka, India
10. Stewart Assay & Environmental Laboratories LLC, Kara-Balta, Chüy, Kyrgyzstan
COA-1919-AC18.10660-R0 Page: 5 of 5
