Hostname: page-component-848d4c4894-jbqgn Total loading time: 0 Render date: 2024-06-25T15:15:40.094Z Has data issue: false hasContentIssue false

Report of the Association Internationale Pour L’étude Des Argiles (AIPEA) Nomenclature Committee for 2001: Order, Disorder and Crystallinity in Phyllosilicates and the Use of the “Crystallinity Index”

Published online by Cambridge University Press:  01 January 2024

Stephen Guggenheim*
AIPEA Nomenclature Committee, Department of Earth and Environmental Sciences, University of Illinois at Chicago, 845 W. Taylor St., Chicago, Illinois 60607, USA
Derek C. Bain
Macaulay Land Use Research Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
Faíza Bergaya
Centre de Recherche de la Matière Divisée (CRMD), National Centre of Scientific Research, University of Orléans, lb Rue de la Férollerie, 45 071 Orléans Cedex 2, France
Maria F. Brigatti
Department of Earth Sciences, Modena and Reggio Emilia University, Largo S. Eufemia 19, I-41100 Modena, Italy
Victor A. Drits
Geological Institute of the Russian Academy of Science, 7 Pyzerskii Per, Moscow J-17 Russia
Dennis D. Eberl
US Geological Survey, 3215 Marine St., Boulder, Colorado, 80303, USA
Milton L. L. Formoso
9500, Ave Bento Gonçalves, Campus do Vale, Institute of Geosciences, University Federal do Rio Grande do Sul, Porto Alegre - RS - Brazil, CEP - 91540-000
Emilio Galán
Department of Crystallography and Minerals, Facultad de Quimica Universite, Sevilla, Spain
Richard J. Merriman
British Geological Survey, Keyworth, Nottingham, NG12 5GG, UK
Donald R. Peacor
Department of Geological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA
Helge Stanjek
Lehrstuhl Für Bodenkunde, Technische Universtät Munchen, D-85350 Freising-Weihenstephan, Germany
Takashi Watanabe
Joetsu University of Education, Joetsu Niigata 943, Japan
*E-mail address for correspondence:


The purpose of this report is to describe the appropriate use of indices relating to crystallinity, such as the ‘crystallinity index’, the ‘Hinckley index’, the ‘Kübler index’, and the ‘Árkai index’. A ‘crystalline’ solid is defined as a solid consisting of atoms, ions or molecules packed together in a periodic arrangement. A ‘crystallinity index’ is purported to be a measure of crystallinity, although there is uncertainty about what this means (see below). This report discusses briefly the nature of order, disorder and crystallinity in phyllosilicates and discusses why the use of a ‘crystallinity index’ should be avoided. If possible, it is suggested that indices be referred to using the name of the author who originally described the parameter, e.g. ‘Hinckley index’ or ‘Kübler index’, or in honor of a researcher who investigated the importance of the parameter extensively, e.g. ‘Árkai index’.

Research Article
Copyright © 2002, The Clay Minerals Society

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)


Árkai, P., (1991) Chlorite crystallinity: an empirical approach and correlation with illite crystallinity, coal rank and mineral facies as exemplified by Palaeozoic and Mesozoic rocks of northeast Hungary Journal of Metamorphic Geology 9 723734 10.1111/j.1525-1314.1991.tb00561.x.CrossRefGoogle Scholar
Árkai, P. and Tóth, N.M., (1983) Illite crystallinity: combined effects of domain size and lattice distortion Acta Geologica Hungarica 26 341 358.Google Scholar
Árkai, P. Sassi, F.P. and Sassi, R., (1995) Simultaneous measurements of chlorite and illite crystallinity: a more reliable geothermometric tool for monitoring low- to very low-grade metamorphisms in metapelites. A case study from the Southern Alps (NE Italy) European Journal of Mineralogy 7 11151128 10.1127/ejm/7/5/1115.CrossRefGoogle Scholar
Árkai, P. Merriman, R.J. Roberts, B. Peacor, D.R. and Tóth, M., (1996) Crystallinity, crystallite size and lattice strain of illite-muscovite and chlorite: comparison of XRD and TEM data for diagenetic and epizonal pelites European Journal of Mineralogy 8 11191137 10.1127/ejm/8/5/1119.CrossRefGoogle Scholar
Árkai, P. Mata, M.P. Giorgetti, G. Peacor, D.R. and Tóth, M., (2000) Comparison of diagenetic and low-grade meta-morphic evolution of chlorite in associated metapelites and metabasites: An integrated TEM and XRD study Journal of Metamorphic Geology 18 531550 10.1046/j.1525-1314.2000.00272.x.CrossRefGoogle Scholar
Brindley, G.W., Brindley, G.W. and Brown, G., (1980) Order-disorder in clay mineral structures Crystal Structures of Clay Minerals and their X-ray Identification London Mineralogical Society 125 196.CrossRefGoogle Scholar
Drits, V.A. Sahkarov, B.A. Salyn, A.L. and Manceau, A., (1993) Structural model for ferrihydrite Clay Minerals 28 185207 10.1180/claymin.1993.028.2.02.CrossRefGoogle Scholar
Drits, V.A. Środoń, J. and Eberl, D.D., (1997) XRD measurements of mean crystallite thickness of illite and illite/smectite: reappraisal of the Kübler index and the Scherrer equation Clays and Clay Minerals 45 461475 10.1346/CCMN.1997.0450315.CrossRefGoogle Scholar
Dunoyer de Segonzac, G. (1969) Les minéraux argileux dans la diagenèse — passage au métamorphisme. Mémoires du Service de la Carte Géologique d’Alsace et de Lorraine, 29, 321 p.Google Scholar
Dunoyer de Segonzac, G. and Bernoulli, D., (1976) Diagenese et métamorphisme des argiles dans le Rhétien Sud-alpin et Austro-alpin (Lombardie et Grisons) Bulletin Societé Géologique de la France 18 12831293 10.2113/gssgfbull.S7-XVIII.5.1283.CrossRefGoogle Scholar
Eberl, D.D. and Velde, B., (1989) Beyond the Kübler index Clay Minerals 24 571577 10.1180/claymin.1989.024.4.01.CrossRefGoogle Scholar
Eberl, D.D. Środoń, J. Lee, M. Nadeau, P.H. and Northrop, H.R., (1987) Sericite from the Silverton caldera, Colorado: Correlation among structure, composition, origin and particle thickness American Mineralogist 72 914 934.Google Scholar
Eberl, D.D. Środoń, J. Kralik, M. Taylor, B.E. and Peterman, Z.E., (1990) Ostwald ripening of clays and metamorphic minerals Science 248 474477 10.1126/science.248.4954.474.CrossRefGoogle Scholar
Essene, E.J. and Peacor, D.R., (1995) Clay mineral thermometry — a critical perspective Clays and Clay Minerals 43 540553 10.1346/CCMN.1995.0430504.CrossRefGoogle Scholar
Flehmig, W. (1973) Kristallinität und Infrarotspektroskopie natürlicher dioktaedrischer Illite. Neues Jahrbuch für Mineralogie, Monatshefte, 351361.CrossRefGoogle Scholar
Frey, M. and Frey, M., (1987) Very low-grade metamorphism of clastic sedimentary rocks Low Temperature Metamorphism Glasgow, UK Blackie & Son Ltd. 9 58.Google Scholar
Hinckley, D.N., (1963) Variability in “crystallinity” values among the kaolin deposits of the coastal plain of Georgia and South Carolina Clays and Clay Minerals II 229 235.Google Scholar
Jaboyedoff, M. Bussy, F. Kubler, B. and Thelin, P.h., (2001) Illite “Crystallinity” Revisited Clays and Clay Minerals 49 156167 10.1346/CCMN.2001.0490205.CrossRefGoogle Scholar
Jiang, W.-T. Peacor, D.R. Árkai, P. Tóth, M. and Kim, J.-W., (1997) TEM and XRD determination of crystallite size and lattice strain as a function of illite crystallinity in pelitic rocks Journal of Metamorphic Geology 15 267281 10.1111/j.1525-1314.1997.00016.x.CrossRefGoogle Scholar
Kisch, H.J., Larsen, G. and Chilingar, G.V., (1983) Mineralogy and petrology of burial diagenesis (burial metamorphism) and incipient metamorphism in clastic rocks Diagenesis of Sediments and Sedimentary Rocks Amsterdam Elsevier 289493 2.Google Scholar
Kisch, H.J., (1990) Calibration of the anchizone: a critical comparison of illite ‘crystallinity’ scales used for definition Journal of Metamorphic Geology 8 3146 10.1111/j.1525-1314.1990.tb00455.x.CrossRefGoogle Scholar
Kisch, H.J., (1991) Illite crystallinity: recommendations on sample preparation, X-ray diffraction settings and inter-laboratory standards Journal of Metamorphic Geology 9 665670 10.1111/j.1525-1314.1991.tb00556.x.CrossRefGoogle Scholar
Kübler, B., (1964) Les argiles, indicateurs de métamorphisme Revue de l’Institut Francaise du Petrole 19 1093 1112.Google Scholar
Kübler, B. (1967) La cristallinite de l’illite et les zones tout á fait supécieures du métamorphisme. In Étages Tectoniques. Collogue de Neuchâtel 1996, pp. 105121.Google Scholar
Kübler, B. and Lagache, M., (1984) Les indicateurs des transformations physiques et chimiques dans la diagenèse, température et calorimétrie Thermométrie et Barométrie Géologiques Paris Societé Francaise Minéralogie et de Cristallographie 489 596.Google Scholar
Li, G. Peacor, D.R. Buseck, P.R. and Árkai, P., (1998) Modification of illite-muscovite crystallite size distributions by sample preparation for powder XRD analysis The Canadian Mineralogist 36 1435 1451.Google Scholar
Merriman, R.J. Peacor, D.R., Frey, M. and Robinson, D., (1999) Very low-grade metapelites: mineralogy, microfabrics and measuring reaction progress Low-grade Metamorphism Oxford, UK Blackwell Science 10 60.Google Scholar
Merriman, R.J. Roberts, B. and Peacor, D.R., (1990) A transmission electron microscope study of white mica crystallite size distribution in a mudstone to slate transitional sequence, North Wales, U.K Contributions to Mineralogy and Petrology 106 2740 10.1007/BF00306406.CrossRefGoogle Scholar
Merriman, R.J. Roberts, B. Peacor, D.R. and Hirons, S.R., (1995) Strain-related differences in the crystal growth of white mica and chlorite: a TEM and XRD study of the development of metapelite microfabrics in the Southern Uplands thrust terrane, Scotland Journal of Metamorphic Geology 13 559576 10.1111/j.1525-1314.1995.tb00243.x.CrossRefGoogle Scholar
Peacor, D.R. and Buseck, P.R., (1992) Diagenesis and low-grade metamorphism of shales and slates Minerals and Reactions at the Atomic Scale: Transmission Electron Microscopy Washington, D.C. Mineralogical Society of America 335380 10.1515/9781501509735-013 Reviews in Mineralogy, 27 .CrossRefGoogle Scholar
Plançon, A. and Zacharie, C., (1990) Ân expert system for the structural characterization of kaolinites Clay Minerals 25 249260 10.1180/claymin.1990.025.3.01.CrossRefGoogle Scholar
Środoń, J. Elsass, F. McHardy, W.J. and Morgan, D.J., (1992) Chemistry of illite-smectite inferred from TEM measurements of fundamental particles Clay Minerals 27 137158 10.1180/claymin.1992.027.2.01.CrossRefGoogle Scholar
Warr, L.N. and Nieto, F., (1998) Crystallite thickness and defect density of phyllosilicates in low-temperature metamorphic pelites: a TEM and XRD study of clay mineral crystallinity-index standards The Canadian Mineralogist 36 1453 1474.Google Scholar
Warr, L.N. and Rice, A.H.N., (1994) Interlaboratory standardization and calibration of clay mineral crystallinity and crystallite size data Journal of Metamorphic Geology 12 141152 10.1111/j.1525-1314.1994.tb00010.x.CrossRefGoogle Scholar
Watanabe, T., (1988) The structural model of illite/smectite interstratified minerals and the diagram for its identification Clay Science 7 97 114.Google Scholar
Weaver, E.W., (1960) Possible uses of clay minerals in search for oil Bulletin of the American Association of Petroleum Geologists 44 1505 1518.Google Scholar
Weber, F. Dunoyer de Segonzac, G. and Economou, C., (1976) Une nouvelle expression de la’ crystalliné’ de l’illite et des micas. Notion d’epaisseur des cristallites Compte Rendu Sommaire de Seances de la Societé Géologique de France 5 225 227.Google Scholar
Weber, K. (1972) Notes on the determination of illite crystallinity. Neues Jahrbuch für Mineralogie, Monatshefte, 267276.Google Scholar