{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,2,13]],"date-time":"2026-02-13T08:00:17Z","timestamp":1770969617977,"version":"3.50.1"},"reference-count":38,"publisher":"Cambridge University Press (CUP)","issue":"3","license":[{"start":{"date-parts":[[2024,1,1]],"date-time":"2024-01-01T00:00:00Z","timestamp":1704067200000},"content-version":"unspecified","delay-in-days":7884,"URL":"https:\/\/www.cambridge.org\/core\/terms"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Clays and clay miner."],"published-print":{"date-parts":[[2002,6]]},"abstract":"<jats:p>The purpose of this report is to describe the appropriate use of indices relating to crystallinity, such as the \u2018crystallinity index\u2019, the \u2018Hinckley index\u2019, the \u2018K\u00fcbler index\u2019, and the \u2018\u00c1rkai index\u2019. A \u2018crystalline\u2019 solid is defined as a solid consisting of atoms, ions or molecules packed together in a periodic arrangement. A \u2018crystallinity index\u2019 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 \u2018crystallinity index\u2019 should be avoided. If possible, it is suggested that indices be referred to using the name of the author who originally described the parameter, <jats:italic>e.g.<\/jats:italic> \u2018Hinckley index\u2019 or \u2018K\u00fcbler index\u2019, or in honor of a researcher who investigated the importance of the parameter extensively, <jats:italic>e.g.<\/jats:italic> \u2018\u00c1rkai index\u2019.<\/jats:p>","DOI":"10.1346\/000986002760833783","type":"journal-article","created":{"date-parts":[[2003,2,4]],"date-time":"2003-02-04T11:44:18Z","timestamp":1044359058000},"page":"406-409","source":"Crossref","is-referenced-by-count":63,"title":["Report of the Association Internationale Pour L\u2019\u00e9tude Des Argiles (AIPEA) Nomenclature Committee for 2001: Order, Disorder and Crystallinity in Phyllosilicates and the Use of the \u201cCrystallinity Index\u201d"],"prefix":"10.1017","volume":"50","author":[{"given":"Stephen","family":"Guggenheim","sequence":"first","affiliation":[]},{"given":"Derek C.","family":"Bain","sequence":"additional","affiliation":[]},{"given":"Fa\u00edza","family":"Bergaya","sequence":"additional","affiliation":[]},{"given":"Maria F.","family":"Brigatti","sequence":"additional","affiliation":[]},{"given":"Victor A.","family":"Drits","sequence":"additional","affiliation":[]},{"given":"Dennis D.","family":"Eberl","sequence":"additional","affiliation":[]},{"given":"Milton L. L.","family":"Formoso","sequence":"additional","affiliation":[]},{"given":"Emilio","family":"Gal\u00e1n","sequence":"additional","affiliation":[]},{"given":"Richard J.","family":"Merriman","sequence":"additional","affiliation":[]},{"given":"Donald R.","family":"Peacor","sequence":"additional","affiliation":[]},{"given":"Helge","family":"Stanjek","sequence":"additional","affiliation":[]},{"given":"Takashi","family":"Watanabe","sequence":"additional","affiliation":[]}],"member":"56","published-online":{"date-parts":[[2024,1,1]]},"reference":[{"key":"S0009860400024009_CR25","first-page":"489","volume-title":"Thermom\u00e9trie et Barom\u00e9trie G\u00e9ologiques","author":"K\u00fcbler","year":"(1984)"},{"key":"S0009860400024009_CR1","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1314.1991.tb00561.x"},{"key":"S0009860400024009_CR6","doi-asserted-by":"publisher","DOI":"10.1180\/mono-5.2"},{"key":"S0009860400024009_CR11","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1989.024.4.01"},{"key":"S0009860400024009_CR17","first-page":"229","article-title":"Variability in \u201ccrystallinity\u201d values among the kaolin deposits of the coastal plain of Georgia and South Carolina","volume":"II","author":"Hinckley","year":"(1963)","journal-title":"Clays and Clay Minerals"},{"key":"S0009860400024009_CR5","doi-asserted-by":"publisher","DOI":"10.1046\/j.1525-1314.2000.00272.x"},{"key":"S0009860400024009_CR15","doi-asserted-by":"publisher","DOI":"10.1127\/njmm\/1973\/1973\/351"},{"key":"S0009860400024009_CR18","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.2001.0490205"},{"key":"S0009860400024009_CR30","doi-asserted-by":"publisher","DOI":"10.1515\/9781501509735-013"},{"key":"S0009860400024009_CR35","first-page":"97","article-title":"The structural model of illite\/smectite interstratified minerals and the diagram for its identification","volume":"7","author":"Watanabe","year":"(1988)","journal-title":"Clay Science"},{"key":"S0009860400024009_CR4","doi-asserted-by":"publisher","DOI":"10.1127\/ejm\/8\/5\/1119"},{"key":"S0009860400024009_CR28","doi-asserted-by":"publisher","DOI":"10.1007\/BF00306406"},{"key":"S0009860400024009_CR23","first-page":"1093","article-title":"Les argiles, indicateurs de m\u00e9tamorphisme","volume":"19","author":"K\u00fcbler","year":"(1964)","journal-title":"Revue de l\u2019Institut Francaise du Petrole"},{"key":"S0009860400024009_CR16","first-page":"9","volume-title":"Low Temperature Metamorphism","author":"Frey","year":"(1987)"},{"key":"S0009860400024009_CR2","first-page":"341","article-title":"Illite crystallinity: combined effects of domain size and lattice distortion","volume":"26","author":"\u00c1rkai","year":"(1983)","journal-title":"Acta Geologica Hungarica"},{"key":"S0009860400024009_CR9","first-page":"321","article-title":"Les min\u00e9raux argileux dans la diagen\u00e8se \u2014 passage au m\u00e9tamorphisme","volume":"29","author":"Dunoyer de Segonzac","year":"1969","journal-title":"M\u00e9moires du Service de la Carte G\u00e9ologique d\u2019Alsace et de Lorraine"},{"key":"S0009860400024009_CR19","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1314.1997.00016.x"},{"key":"S0009860400024009_CR13","doi-asserted-by":"publisher","DOI":"10.1126\/science.248.4954.474"},{"key":"S0009860400024009_CR7","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1993.028.2.02"},{"key":"S0009860400024009_CR14","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1995.0430504"},{"key":"S0009860400024009_CR26","first-page":"1435","article-title":"Modification of illite-muscovite crystallite size distributions by sample preparation for powder XRD analysis","volume":"36","author":"Li","year":"(1998)","journal-title":"The Canadian Mineralogist"},{"key":"S0009860400024009_CR32","doi-asserted-by":"publisher","DOI":"10.1180\/claymin.1992.027.2.01"},{"key":"S0009860400024009_CR29","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1314.1995.tb00243.x"},{"key":"S0009860400024009_CR22","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1314.1991.tb00556.x"},{"key":"S0009860400024009_CR21","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1314.1990.tb00455.x"},{"key":"S0009860400024009_CR3","doi-asserted-by":"publisher","DOI":"10.1127\/ejm\/7\/5\/1115"},{"key":"S0009860400024009_CR24","unstructured":"K\u00fcbler, B. (1967) La cristallinite de l\u2019illite et les zones tout \u00e1 fait sup\u00e9cieures du m\u00e9tamorphisme. In \u00c9tages Tectoniques. Collogue de Neuch\u00e2tel 1996, pp. 105\u2013121."},{"key":"S0009860400024009_CR8","doi-asserted-by":"publisher","DOI":"10.1346\/CCMN.1997.0450315"},{"key":"S0009860400024009_CR10","doi-asserted-by":"publisher","DOI":"10.2113\/gssgfbull.S7-XVIII.5.1283"},{"key":"S0009860400024009_CR27","first-page":"10","volume-title":"Low-grade Metamorphism","author":"Merriman","year":"(1999)"},{"key":"S0009860400024009_CR34","doi-asserted-by":"publisher","DOI":"10.1111\/j.1525-1314.1994.tb00010.x"},{"key":"S0009860400024009_CR12","first-page":"914","article-title":"Sericite from the Silverton caldera, Colorado: Correlation among structure, composition, origin and particle thickness","volume":"72","author":"Eberl","year":"(1987)","journal-title":"American Mineralogist"},{"key":"S0009860400024009_CR38","unstructured":"Weber, K. 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